Eclipse's Memory purchasing guide

(cf)Eclipse

Freelance Overclocker
Joined
Feb 18, 2003
Messages
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This is meant for those of you who are looking to buy new memory for your rig. I will try to make it as comprehensive as I can, so if there is anything you think I missed, feel free to post and let me know :cool:

That said, let's get to work. I'll divide the important topics into seperate posts so that you can go and read that post directly instead of having to look through one big post for info that pertains to your situation.

The types of DRAM - Which does your system need?
Memory Timings and Speed - How important it is for performance
Memory Size - How much is needed, and why
The Memory itself - What you should get based on the above information

Keep in mind that this thead will be a work in progress. i plan to add some info on the various timings at some point (after i finish up that part of the review for EclipseOC), and a more thorough list of ram chips when i get the time :cool:
 
Types of DRAM
Which is best for you? Read through this and decide what features your system requires in your ram.



DDR-1 vs. DDR-2
For now, this is a relatively simple thing to figure out, and the only motherboards that support DDR-2 are Intel based. Check your motherboards documentation for further details.
DDR is 184pins while DDR2 is 240pins.
AMD will launch new sockets to support DDR2 next year during Q2 or Q3, called S1 (mobile) M2 (desktop) and F (server)



What Speed?
To clear up some confusion that some people seem to have, mhz and DDR speeds are different. I've seen countless posts from people asking why their ram is running at 200mhz, not the 400mhz it should be. Simply put in numbers:
200mhz = DDR400 = PC3200
Just multiply the mhz of the ram by 2 to get the DDR speed, then by another 8 (or mhz*16) to get the PC rating.

My opinion here, but you should buy the fastest memory your motherboard supports, assuming budget allows.
If you intend to overclock, it might be wise to consider some memory that is over the rated speed of your motherboard, but it is not needed. I have seen DDR400 memory do >300mhz, and I've seen DDR500 ram top out at 265mhz. It all depends on how you overclock, what the rest of your rig is, and how much of a budget you have. I'll touch on this a bit in other topics.



The Importance of Timings
As a general rule of thumb, the lower the timings, the better. Low timings means the memory controller can access data inside the ram sticks in less time, improving responsiveness a slight amount, and generally improving overall performance. Typically, there is a tradeoff between timings and mhz. If you want higher mhz, you will have to settle for higher timings.
Also, at a given mhz and size, low latency ram is almost always more expensive than high latency ram.



Unbuffered vs Buffered/Registered and if ECC is important
First, I'll touch on ECC. Think of ECC as a superset of DRAM. If both the Motherboard and Memory support ECC, it can be enabled, but doesn't have to be. A non-ECC ram stick will work in an ECC supporting motherboard just as an ECC stick will work in a motherboard that doesn't support ECC.
ECC is basically a way to check for errors (duh :p). Those of you who need it will know why this is important. If you don't know, you most likely don't need ECC.

Unbuffered RAM is what is used in the majority of desktop motherboards. Registered RAM is typically used in a server environment.
Basically, Registered RAM has a little buffer that incurrs a performance hit, but allows for much better loading on the memory controller to allow for many more sticks to be used, thus why it's typically used in servers or computers that definitly need a lot of Memory Capacity.
 
RAM Speed & Timings
How it effects overall performance


Latency is a function of RAM timings and mhz. The higher the mhz is at a given set of timings, the lower latency will be, and the lower the timings are at a given mhz, the lower the latency will be. Usually timings have a larger impact on latency than mhz, but the range of usable timings is usually pretty small while mhz is not, making them equally important.
Bandwidth is very dependant on mhz, but timings also play a moderate role. Higher mhz means more bandwidth, while lower timings means more bandwidth.

Some programs like lower latency more than higher bandwidth, and vice versa. As a general rule of thumb:
Tasks that are very streaming in nature, such as video/audio encoding, are more dependant on bandwidth than latency.
Math oriented programs, like superPI and most games, see a bigger benefit to lower latency than high bandwidth.

As always, there is a tradeoff between timings and mhz that yeilds optimal performance. It can be predicted what the optimal timings will be to get the highest mhz without sacrificing latency too much. Here is a quick guide that will probably be edited for future reference:
Samsung TCCD and TCC5: Sweet spot is usually with 2.5-3-3, sometimes with 2.5-4-3
Micron 5b C and 5b G: Usually 3-2-3 or 2.5-2-3
Winbond BH/CH (UTT): 1.5-2-2 or 2-2-2 will be optimal with as much voltage as you feel safe supplying, or can.
Micron 5b D, Samsung UCCC and Infineon BE-5 all seem to like 3-3-3 the most. these chips are used in single sided 512mb and 1024mb sticks.



AMD K8 CPU's (s754, s939 and s940)
Due to it's integrated memory controller and well balanced front end, K8 CPU's are relatively insensitive to memory performance outside of benchmarks. Robberbaron and myself have touched on this topic already; showing a moderate change in performance with mhz in benches, but a small difference in real world applications.
Also, since the memory controller opterates at the same speed as the CPU, memory efficiency increases as CPU mhz goes up. Latency is effected the most, but CPU mhz also has a moderate impact on Bandwidth. I did some testing to demonstate the effect on latency. At 200mhz, the timings are 2-2-2-10, while at 230mhz the timings are 2.5-2-2-10. I kept the ram speed constant for each range throughout testing while only varying CPU speed. Obviously, it has diminishing returns, but it shows the effect quite well.
And one last benefit of having an integrated memory controller: Since the memory speed is always divided from the memory controller, using a divider in the BIOS will not effect performance outside of the actual mhz difference. Have a look at how the divider really works.



AMD K7 CPU's
Not much to say here. It's moderately sensitive to both mhz and timings.
One thing to keep in mind, for some reason, the Memory divider has a relatively major impact on memory performance.. enough that I would recommend trying to avoid using a divider at all costs on a K7 board.



Intel Netburst CPU's
These CPUs are bandwidth hogs for the lack of a better term. In most cases, more mhz is better than tighter timings. As the CPU speed scales up, it'll want more and more bandwidth from the memory to keep the core fed with data. The 2mb cache Prescott is a bit less dependant on bandwidth than it's smaller cached brothers.
Memory dividers do effect ram performance a bit, but not a whole lot. As a rough rule of thumb, if you do use a divider to get higher CPU mhz when overclocking, try to make sure that the CPU gain is at least 2-3 times the drop in ram mhz to try to offset the performance hit from the divider and slower ram.
 
Memory Size
How much is needed and why.


This is a very program and budget specific problem. Here's my quick reccomendations, without taking into account every single possible scenario :D

512mb -> This would be the least amount of RAM I would want in a computer, no matter what. This is good if you're on a tight budget, or don't do anything past browsing teh intarweb and checking the emails on your computer.

1024mb -> A good happy medium. Good for computers that run moderately intensive programs like video or image editing, play games or do some light rendering work. Also, if you plan on doing some moderate to heavy overclocking, 512mb sticks are often the best value for the performance.

2048mb -> I reserve this for the heavy media computers, the people who need all out performance when dealing with large files/pictures or very high quality rendering. The most recent batch of games *cough* BF2 *cough* love having 2gb of RAM too, so if the computer will be doing hardcore gaming, 2gb is an option to consider. The problem is that there is a tradeoff between latency+mhz for the high density chips that are used in 1gb sticks.


Things to consider
Budget: more memory.. costs more.
Overclocking: high density memory typically doesn't overclock as well as normal density
The rig: This pertains to K8 CPU's more than anything else. Filling all the memory slots (DIMM's) with ram is an unwise idea, due to the loading abilities of the integrated memory controller. As a quick guide, these are the limitations
s939, revE cpu:
4 double sided sticks = 200mhz, 2T command rate
4 single sided sticks = 200mhz, 1T command rate (assuming the mobo is capable)

s939, non-revE cpu:
4 double sided sticks = 166mhz, 2T
4 single sided sticks = 200mhz, 2T

for s754, it's the same thing, but for 3 sticks instead of 4.
Robberbaron has touched on this topic for the K8's already
 
The Memory itself
What you should get based on the above information

This is where things aren't so clear cut. It is generally wise to stick to known brands.

for 1gb sticks, there are only 2 or 3 I would really consider
budget - G.skill pc3200 for some overclocking or stock speeds. g.skill also makes a DDR500 set that costs about the same amount that often oc's pretty well too.
If you've got money and plan to overclock, get crucial ballistix (which have had some failure issues as of late, but i feel the problem will resolve itself soon), or something based on infineon CE-6, which means either the OCZ or Mushkin 1gb pc4000 sticks that are rated for 3-3-2. both are very difficult to find in stock though :(


512mb sticks.. there are a lot more options.
budget:
crucial value
kingston value
corsair value select (though i personally don't like this stuff, some people do)
if you plan on overclocking on a budget, same as the 1gb, go with the crucial.

moderately priced performance, good for overclocking
crucial ballistix pc3200 - uses micron chips, usually 5b G, but i've seen a single sided 5b D stick before. It typically overclocks to 235-250mhz at 2.5-2-2, 250-270mhz at 2.5-3-3 and 265-300mhz at 3-3-3, and scales decently with voltage, but doesn't need it.
patriot XBL pc3200
OCZ platinum rev2 pc3200
the patriot and ocz both use samsung TCCD or TCC5 chips. These should be able to do 250mhz at 2.5-3-3 at the least, and if you're lucky, 270-290mhz at 2.5-3-3

all out overclocking ram, price be damned:
OCZ pc4800
Patriot pc4800
again, TCCD or TCC5. I'm fairly certain the OCZ is TCCD only. This is the top bin of the samsung chips. Assuming your system is capable, these sticks should be able to do 315-340mhz


256mb sticks, mainly used for those on a serious budget, or want cheap oc'ing benching ram. For this reason I will only cover the low end and high end stuff.
TwinMOS pc3200
GeIL Value pc3200
Mushkin SP3200

overclocking goodness.. as single sided 256mb sticks often clock better than double sided 512mb
GeIL ONE



now.. i think that should cover just about everything.
 
Seems you use Crucial or nothing at all! LOL

I currently have a decent OC with a (2x512) gig of Mushkin Value ram. Venice 3k oc'ed to 2.4. :D My timings are pretty decent too. 2.5 - 3 - 3 -7. Voltage on ram is 2.8. Abit AN8 mobo and HS is a Zalman 7700. CPU idles high 20's and high 30's under full load. 40's if room is warm.

Question is: Will "more expensive" ram function better at those same timings?

Let's say - will Ballistix or OCZ Platinum 2.0 or PDP X series at the same timings of 2.5-3-3-7 cause the system to perform better? Reason I name those is because those are the ones I'm looking at. I also have Geil Ultra's but needs 3.1 and I only have 2.8 on voltage.
:( After seeing my OC I'm of dumping the Geil's!!! I couldn't get them past 227 stable.

If there is no difference to the performance of the computer why in the world would one pay 2-3x more for memory? :confused:

Thanks
 
MC FLMJIG said:
Seems you use Crucial or nothing at all! LOL

I currently have a decent OC with a (2x512) gig of Mushkin Value ram. Venice 3k oc'ed to 2.4. :D My timings are pretty decent too. 2.5 - 3 - 3 -7. Voltage on ram is 2.8. Abit AN8 mobo and HS is a Zalman 7700. CPU idles high 20's and high 30's under full load. 40's if room is warm.

Question is: Will "more expensive" ram function better at those same timings?

Let's say - will Ballistix or OCZ Platinum 2.0 or PDP X series at the same timings of 2.5-3-3-7 cause the system to perform better? Reason I name those is because those are the ones I'm looking at. I also have Geil Ultra's but needs 3.1 and I only have 2.8 on voltage.
:( After seeing my OC I'm of dumping the Geil's!!! I couldn't get them past 227 stable.

If there is no difference to the performance of the computer why in the world would one pay 2-3x more for memory? :confused:

Thanks

Yes, he is a bit of a crucial whore...he really should get commissions from them.
 
tsuehpsyde said:
Yes, he is a bit of a crucial whore...he really should get commissions from them.
haha, i didn't mention crucial too much in this, but yes. well.. no. i'm a micron whore. crucial is the best place to get good micron :D


MC FLMJIG said:
Question is: Will "more expensive" ram function better at those same timings?
i wasn't aware that the price of something had anything to do with it's performance at given settings :D
(read: no.)
 
I would have to give the Patriot pc4800 the best bang for the buck. My sticks have done well over 300mhz 2.5,4,3,7 . And when running at 200 1.5,2,2,5. And they don't require crazy volts to do it...
 
That's very interesting indeed. So I guess I wont be going out to spend more $ on ram then!!! Thanks!!!

Curiosity - Will a computer run better at say 2 2 2 6 at 200FSB or 2.5 3 3 7 at let's say 250FSB or even 3 3 3 7FSB?

Just curious because I've never seen questions like these posted before.

Without owning a stick of ram how can you tell it if Micron chips are inside?
 
for the first question, 2.5-3-3 or 3-3-3 at 250mhz should be a bit better than 2-2-2 at 200mhz

second, you make an educated guess :D
 
Just for the record.. Eclipse is the person who originally gotten me into Crucial/Micron, and I have had nothing but superb experiences. If I were to run out now and buy new memory, it'd be Crucial.. it overclocks like a dream and comes in at a great price.

^^ Not meant as an advertisment.
 
Thanks for the answers!!! ;)

I guess I'm sitting tight with what I have now. I was leaning towards the 3 co's you mentioned, before I read this thread anyway, but I believe at the I'm getting decent performance at the moment. I was a little skeptical on the Ballistix as I've read many stories on how it goes bad within a few months. (It does have a lifetime warranty but who wants to go through that hassle?) I guess they just don't know how to tweak or maybe just "burned" them or maybe just a few bad sticks.

Thanks!
 
is there really anything wrong with high density ram? I mean, I bit on the cheap HD ram offered in the HOTDEALS section and seriously feel pretty good about it. I mean, it OCs fairly well--as much as I care at the moment to OC and was CHEAP as freaken hell.

That said, am I really missing anything by not being able to run at tight settings. Should 2gigs outweigh any losses tighter timings would give?
 
Eclipse, great post but you should update your post about Crucial 1GB modules.
On Newegg at least, they have been replaced by the Samsung UCCC chips (M16FD), which don't overclock as well. I can also confirm this for the crucial 8T single sided 512MB modules as well. These UCCC chips suck. I have 4 of these 8T (3 original and 1 samsung UCCC) and I can only do 2T at 140/200 MHz even though they're single sided.

If you look at the buyer reviews for the 1GB stick, you'll see what I mean.

Buyer beware.

Patriot seems to be a better option to me right now.
 
cambrian said:
Eclipse, great post but you should update your post about Crucial 1GB modules.
On Newegg at least, they have been replaced by the Samsung UCCC chips (M16FD), which don't overclock as well. I can also confirm this for the crucial 8T single sided 512MB modules as well. These suck. I have 4 of these 8T (3 original and 1 samsung UCCC) and I can only do 2T at 140/200 MHz even though they're single sided.

Buyer beware.

Patriot seems to be a better option to me right now.
yeah, i know the 1024mb sticks are now samsung UCCC, but most reports that i have been seeing put it a bit worse than the 5b D (like 230-245mhz), perhaps you got bum sticks?. thanks for the info on the .8T sticks, have you gotten any of the double sided recently, or have you specifically been ordering single sided?
i think micron is just having an issue meeting the sudden demand for high density chips.. the only question would be how long it takes them to get supply going again.


MC FLMJIG said:
I was a little skeptical on the Ballistix as I've read many stories on how it goes bad within a few months.
i've had two sticks for almost a year now, and i've done some stupid things to them, including running at 3.2v for a while. doesn't seem to effect it at all. i think most of the problem with ballistix deaths is from insufficient cooling, as the stuff runs pretty hot.


Pkirk: what do you do with your rig? i think i outlined your answer pretty well already, just read the guide ;)
 
i have specifically been ordering the single sided 8T stick. I actually RMA'ed it recently thinking they made a mistake in shipping but I think they'll just send back to me another of the same kind. If you look carefully at the 8T chip description page on Newegg, it has both a picture of the old chip and the new one. It's stupid because most likely you'll get the new (crappier) ones 100% of the time. They fail to mention any of this in the item description and they haven't updated their model number.

Newegg is really slacking off. And what's with the outrageous shipping for an almost feather weight item like this one? (I think they charge me 6 bucks)
 
this is a good point. however, i don't think the FBGA is worse than the TSOP version of 5b D.. it's the same ram IC's, and FBGA is technically superior to TSOP, less resistance, capacitance and inductance :D
it also seems that the normal 512mb stick has two pictures of TSOP chips, one with an ending of simply .16T (doing some quick photo editing makes me thing i see a G written on the chips themselves), and the other being .16TG2, which definitly means 5b G chips, the same stuff used in 512mb ballistix most often. maybe i need to buy a stick to figure some things out :cool:
http://www.newegg.com/Product/Product.asp?Item=N82E16820146532
 
cambrian said:
i don't think we're talking about the same thing lol.
we are. all micron 5b D has been replaced by samsung UCCC in the value line until micron can get it's supply back up. the ballistix remains 5b D, a rep at crucial confirmed this for me.

5b D is used in 512mb single sided and 1024mb sticks
 
I see what both of you are speaking about.

Crucial (Newegg) show 2 modules of 512 PC 3200. One is model CT6464Z40B and the other adds .8t at the end. On both it shows 2 versions of each chip. As pointed correctly, by both, the the CT6464Z40B has 2 chips one with .19T at the end and one with .16TG2 at the end (this one made in UK btw).

The CT6464Z40B.8T has 2 pics as well. One is a .8t and the other is a M8FD.

Newegg also has a dual channel 512 which uses the M8FD (which is costs more :mad:) and the 1Gb Dual Channel which uses M16FD.

LOL How in the world can you guys tell by the model what uses what? :p
I've searched the crucial site and I couldn't find anything.

I also didn't see the .8T on the site either.

Now here you guys threw me off. If single sided is better at OC (from what I've heard (at least on AMD systems)) then why is the 2x sided one, using the .16TG2, better?

Seems like site is having trouble today.
 
MC FLMJIG said:
Now here you guys threw me off. If single sided is better at OC (from what I've heard (at least on AMD systems)) then why is the 2x sided one, using the .16TG2, better?
because the 5b D is higher density than 5b G, thus the latter typically overclocks better :D
 
serbiaNem said:
Just trying to get another sticky eh? Great post.
always, thanks :D
douglite actually gave the idea a while ago.. finally got around to doing it ;)
 
damn so should i just refund my samsung UCCC chip and wait for crucial's supply to go back up? i wonder how long that's going to take.
 
eh.. i don't think i would unless the extra few fps are really that important :)
 
CT6472Z40B This is also another 512 pc3200 by crucial on Newegg. The model is shown inside a "elec" bag and outside. On the bag it has .18T on the end and the one outside the "bag" has a .9t at the end. How confusing!!! One of the reviews actually said he had a real high OC on this ECC ram!!!
 
i returned my stick to newegg and they gave me a complete refund and even refund the shipping fee. Newegg customer service never ceases to amaze me.

I end up getting an 8T from ebay for a cheaper price.
will let you know how well it overclocks.
 
MC FLMJIG said:
CT6472Z40B This is also another 512 pc3200 by crucial on Newegg. The model is shown inside a "elec" bag and outside. On the bag it has .18T on the end and the one outside the "bag" has a .9t at the end. How confusing!!! One of the reviews actually said he had a real high OC on this ECC ram!!!
that is ECC. read the part about registered ram and ECC and you'll see if you really need it or not. :p
(also.. most crucial value does overclock really well. when i first suspected the 1gb sticks to do well, i got a stick, it does 263mhz :cool: )


cambrian, nice to hear. hopefully the .8T will be .8TD, not .K8TK :D
 
No, I don't need ECC. Just found it interesting that an ECC could be OC'ed that high. Guy on Newegg claims 285 FSB, wow.

I know this ram usually runs a tad slower because of the error checking but If it's oc'ed that high might that be worth it? Even if it was 250 FSB I believe that's somewhat impressive.
 
he might have just been lucky, who knows. take my 1gb crucial value stick for example, it does 263mhz while a lot of guys are having trouble hitting 250mhz. also, you can always disable ECC, if your motherboard lets you turn it on in the first place :p
another thing to consider.. if it's for a server market, it's possible that there are stricter requirements on the chips, thus they are higher quality and overclock better, similar to what i'm banking on for the opteron 144. i guess there's one way to find out :p :D
 
(cf)Eclipse said:
always, thanks :D
douglite actually gave the idea a while ago.. finally got around to doing it ;)
I just thinks it's a shame that Eclipse needs to make 50 posts/day telling people to buy Micron 5b G - a sticky would probably catch about half of them :D Besides, keeping a memory guide is easier than keeping a HDD guide, at least I thought. I expected one post telling people to buy the Crucial 1GB sticks, instead I got a four post guide :eek: Puts my guide to shame.
 
DougLite said:
I expected one post telling people to buy the Crucial 1GB sticks, instead I got a four post guide :eek:
heh, if i'm gonna do something the real way, i gotta do it the hard way too :cool:
besides, i actually wrote most of this up while i was bored during class, came back to my room, moved it from paper to computer, fixed it all up and added some links. thanks for the good words though :)
i pm'ed BBS about getting a sticky.. he hasn't replied yet :(
 
Okay I have a question. It's "kinda" off topic. :)

I've read a decent amout of the links on this thread but I'm studying for my life and health license so all the reading is driving me nuts!!!
Certain things I'm still a little confused with.

I keep reading that memory doesn't have much an effect on A64 because of the built in die and that is why using the dividers is ok. I also read elswhere that if you want the ram as close as the original frequency as possible. (ddr 400 I currently have)

Here are my specs:
2.5 3 2 6 on Mushkin value ram 2x 512
FSB = 267
9x = multi
HT = 3x

Voltage:
cpu = 1.4 (on cpu-z = 1.425)
ddr = 2.75
n4 = 1.6
ht = 1.25

Okay now if i have the fsb at 267 and the divider on 133 (2:3) my ram then runs at ddr 355. It's 50 away from pc3200.

Am I better off running my rig at 250 FSB bringing up the divider one? Or leaving alone? Tweaking? Maybe I can try and up the FSB a bit more? What are some suggestions?
:confused:

BTW YOur posts really are very helpful. Clear and concise. Thanks
 
you're best off running the ram as fast as you can without sacrificing cpu mhz :D

in your case, bring the divider up as high as you can without compromising the stability of the rig :cool:
 
I was thinking on that. I know it can do 250 on (333) 166. I really didn't try tweaking much there and just wanted to get to 2.4 heh heh

2.2 is not a bad OC on value ram but I'm greedy and I really wanted 2.4. :D

We'll see what happens. Again thanks.
 
hey eclipse, the guy i bought it from had two version of the 8T

one just says 8T and the other 8TDX. I asked him for the 8T only.

Is this bad? Is the 8TDX same as the 8TD you were talking about?
 
yeah, it still uses the micron 5b D chips.. i dunno what the X is for on the end though
 
what about the 8T only version? would that be -5B C?

I have two 8T2 that are 5B C

For some reason they don't oc that well. they should be though.

I have them running at 210 Mhz 1T 3-3-3-8 2.9V
But if i go any higher than 210, it would freeze at bootup

I thought 5B C were used or similar to the OCZ EB series and those oc well.
 
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