Question about Conroe FSB and Memory speeds

[TeknoZX]

Ok. I'm thinking of getting a new Conroe system when it comes out but need some info to help me allocate the correct parts. I plan on a E6600 which is 2.4 and am shooting for the best 1:1. Overclocking a given.

2400 / 9 = 266.66

2400 being the clock speed and 9 being the multiplier. So we get a base FSB speed of 266.66. However, Intel's chips are quad pumped, Conroe still is I believe, which makes the 266.66 * 4 = 1066

Now, you want ram to match the FSB speed right? Which would be 1066. However, the memory is dual channel so you need half of that. 533. Now, DDR is naturally double data so you need 266 speed DDR2 ram right? I believe that's DDR2-533 which is..PC2-4200?

My question is, first off, is everything I said up there right? I hate confusing myself with all this double this, quad that and stuff.

Next, now for 2.4 at 1:1, DDR2-533 is just right right? So when I read about people saying go for DDR2-1000, PC2-8000, they mean get it so you have head room with the memory to OC right? So theoretically, with dual channel DDR2-1000, you can have a 2000 FSB?

I looked at the table evilmedic posted but I just wanted to make sure I understood correctly. I guess I'm just mostly confused about the DDR2 nomenclature. Freakin with the DDR2 name and the PC2 name being effective bandwidth. Why can't they just all just list it with their clock speeds? That goes for Intel and Amd. I know it's a marketing thing but damn..

 

[chrisf6969]

There is a sticky reguarding Conroe http://www.hardforum.com/showthread.php?t=1059317

But the questions you're asking also pertain to a P4 system with quad bus & DDR2.

To be exact a P4EE system with 1066FSB. The chipset are the same (975) or very similiar 946 / 965. Same ratios, FSB speeds, etc..

IE: Old information that you should be able to find many places.

 

[Donnie27]

Ok. I'm thinking of getting a new Conroe system when it comes out but need some info to help me allocate the correct parts. I plan on a E6600 which is 2.4 and am shooting for the best 1:1. Overclocking a given.

2400 / 9 = 266.66

2400 being the clock speed and 9 being the multiplier. So we get a base FSB speed of 266.66. However, Intel's chips are quad pumped, Conroe still is I believe, which makes the 266.66 * 4 = 1066

Right

Now, you want ram to match the FSB speed right? Which would be 1066. However, the memory is dual channel so you need half of that. 533. Now, DDR is naturally double data so you need 266 speed DDR2 ram right? I believe that's DDR2-533 which is..PC2-4200?

DDR2 is quad pumpped as well. 533 is 2 X 266 to equal 533MHz Effective. Then ran in Dual channel mode.

My question is, first off, is everything I said up there right? I hate confusing myself with all this double this, quad that and stuff.

Next, now for 2.4 at 1:1, DDR2-533 is just right right? So when I read about people saying go for DDR2-1000, PC2-8000, they mean get it so you have head room with the memory to OC right? So theoretically, with dual channel DDR2-1000, you can have a 2000 FSB?

Yes and No. You match bandwidth first, then speed. That scenario you pointed out would be 2000MHz of RAM speed with about 16.GB of bandwdith. But the damned Latency would be so high most gains might be wasted.

I looked at the table evilmedic posted but I just wanted to make sure I understood correctly. I guess I'm just mostly confused about the DDR2 nomenclature. Freakin with the DDR2 name and the PC2 name being effective bandwidth. Why can't they just all just list it with their clock speeds? That goes for Intel and Amd. I know it's a marketing thing but damn..

They do list it as such.
533MHz RAM and is ran in Dual Channel to equal 1066MHz FSB but only 8.4GB of bandwith.

Per Picewatch. Look at it this way;
$229 - pc2-8500 ddr2-1066 1gb is 8.5GB of Bandwidth @ 1066MHz Speed.
$187 - pc2-8000 ddr2-1000 1gb 8GB @1GHz
$117 - pc2-6400 ddr2-800 1gb 6.4GB@800MHz
$66 - pc2-5300 ddr2-667 1gb 5.3GB @667MHz
$65 - pc2-4200 ddr2-533 1gb 4.2GB@533MHz

Of course those represents a rounded numbers and in Dual Channel. 1:1 1066:1066 not even great for stock since if the Processor is using 100% of the RAM's bandwidth, DMI, DMA and etc., causes a hit when they are pushed, this is a small hit but it can be noticed. The more the system is pushed like Multitasking, the easier it is to notice this.

Two channels of PC2-6400 is equal to 12.8GB and 800MHz Dual Channel 1600MHz effective. This covers the 10.6GB of bandwidth that the Processor uses via FSB and leaves extra bandwidth 2.2GB for DMI-I/O and or Video -DMA. If you use faster RAM, it can be ran at 4:5 that equals 1066 FSB to 1333MHz RAM RATIO. Now if you can run this 1:1, that same 9X multiplier gets you 9 X 333.34 = 3GHz. Then I'd want at least good DDR2-667 and do it 1:1 or 4:5 with DDR2 800.

Faster RAM that has higher latency will mean diminishing returns. I'm looking at mid-ranged PC2-8000 to high end or mid-ranged DDR2-667 for light overlcocking.

 

[Poncho]

DDR2 is quad pumpped as well. 533 is 4 X 133 to equal 533MHz Effective. Then ran in Dual channel mode.

Actually.... DDR2 is "double pumped" then ran in dual channel for an effective speed of 4 times the memory speed. DDR2/533 is (266mhz x 2) x 2 (if you are running dual channel) for an effective speed of 1066. So that would match up at a 1:1 ratio with a FSB of 1066mhz. Make sense? we're probably saying the same thing. LOL

Now... my advice to the OP, if you are overclocking.... get the highest speed you can. If you don't want to overclock get DDR2800. IMHO... I would buy nothing less that 800mhz DDR2 if I was going to buy memory now. Should you upgrade to a 965+ chipset you'll see a noticable difference in using DDR2/800

 

[Donnie27]

Actually.... DDR2 is "double pumped" then ran in dual channel for an effective speed of 4 times the memory speed. DDR2/533 is (266mhz x 2) x 2 (if you are running dual channel) for an effective speed of 1066. So that would match up at a 1:1 ratio with a FSB of 1066mhz. Make sense? we're probably saying the same thing. LOL

Now... my advice to the OP, if you are overclocking.... get the highest speed you can. If you don't want to overclock get DDR2800. IMHO... I would buy nothing less that 800mhz DDR2 if I was going to buy memory now. Should you upgrade to a 965+ chipset you'll see a noticable difference in using DDR2/800

You're right it is DDR dual not SDR Quad.

Here's what threw me off.

http://www.digit-life.com/articles2/ddr2-rmma/ddr2-rmma.html

In this case, the core of the memory chips is synchronised at a frequency twice as low as the external one (100 MHz) while DDR synchronises the internal and the external data flows at the same frequency (200 MHz). Therefore, such approach enables to increase the percentage of chip yield and lower energy consumption. By the way, it also explains why the DDR2 standard implies the existence of DIMMs with a 800-MHz effective frequency (which is twice as high as the current DDR generation has). This frequency can be reached right now if we have DDR-400 memory chips working at a 200-MHz core frequency and execute a 4n-prefetch data selection bas ing on the scheme above.

 

[WickedWeasel]

Mushkin PC2-5300 2GB 2X1GB DDR2-667 CL4-4-4-12 240PIN DIMM Dual Channel Memory Kit
http://search.ncix.com/displayproductdetail.php?sku=15194&vpn=991382&manufacture=MUSHKIN


If i get the Mushkin memory above and i overlock the 2.4GHz conroe to 3.33GHz, then the RAM will have to be overlocked 10% from 667MHz to 734MHz.

The question is, will the timings of 4-4-4-12 change?

I don't know if I will be getting 667MHz or 800MHz RAM because the production conroe is not out yet, and we still don't know how well it will overclock on air and stock voltage. But if I get the 667MHz RAM and overclock it a bit, I can save a few bucks.

Another question, are timings of 5-5-5-12 really that bad for the conroe?

 

[Poncho]

Are you going to buy a 965 chipset board? If so... go with DDR2/800, you will notice a performance difference, regardless of overclocking.

 

[Donnie27]

Mushkin PC2-5300 2GB 2X1GB DDR2-667 CL4-4-4-12 240PIN DIMM Dual Channel Memory Kit
http://search.ncix.com/displayproductdetail.php?sku=15194&vpn=991382&manufacture=MUSHKIN


If i get the Mushkin memory above and i overlock the 2.4GHz conroe to 3.33GHz, then the RAM will have to be overlocked 10% from 667MHz to 734MHz.

The question is, will the timings of 4-4-4-12 change?

I don't know if I will be getting 667MHz or 800MHz RAM because the production conroe is not out yet, and we still don't know how well it will overclock on air and stock voltage. But if I get the 667MHz RAM and overclock it a bit, I can save a few bucks.

Another question, are timings of 5-5-5-12 really that bad for the conroe?

I'm really only going for CAS4 4-4-12 PC2 8000.

 

[sp1nfer]

wouldn't the ATI RD600 chipset boards have independent DDR memory controller, thus allowing for independent memory and FSB overclocking?

 

[Donnie27]

wouldn't the ATI RD600 chipset boards have independent DDR memory controller, thus allowing for independent memory and FSB overclocking?

Just about any board with Ratio settings are almost made that way, yes.

 

[sp1nfer]

Just about any board with Ratio settings are almost made that way, yes.

I thought that ATI had something new here, given that they made such a big deal about it.

 

[CoW]8(0)]

The check marks are there just in case you had no idea what 'YES' means

 

[chrisf6969]

This sounds like it may be completely indedpendent. (not ratio driven)

In the past using an "independent" bus (odd ratios) for the memory caused out of sync problems with some northbridges. (ie: introducing unwanted latencies from the mismatched buses) Videocards seemed to have solved this a long time ago, as you can overclock the memory in 1Mhz increments completely independent of the GPU core, etc.

Maybe someone finally developed a northbridge memory control right, where the memory can be clocked to any speed, and not cause any latency problems there by letting you COMPLETELY max out your specific ram at any FSB. That would be SWEET. And it could give Intel a big boost on their memory side considering that AMD has it built in to the chips and working on ratios.

 

[sp1nfer]

The check marks are there just in case you had no idea what 'YES' means

ROFLMAO

chrisf6969, the only ones I see gaining from this is enthusiasts which make a very, very, low share on the big side of things (like 4% or less) and ATI from their spread of the chipset. Do you think Joe 'Blow' Sixpacks who just got his paycheck cares about the 'independent memory controller' or 'reduced memory latency' the seller tells him about? Nah.... He just wants to get either the biggest and fastest or something to browse and game occasionally.

But on to the point, yes it will be very sweet the moment it's released

 

[Donnie27]

I thought that ATI had something new here, given that they made such a big deal about it.

No, it is NOT new. If they are not independent, then you can't lock one and move the other up and down. Clock Gens will still adjust the FSB to RAM Ratio no matter what. They have to sync in the end or problems crop up.

I875, I lock my FSB to 250MHz and Run my RAM within any SPD speed accepted by the system. This ranges from 133 to 300. I can do the in 1MHz increments or by Ratios.

 

[thecoldanddarkone]

I don't see a single benefit on those charts...

 

[pxc]

I don't see a single benefit on those charts...

LOL

I do like that memory speed is independent of FSB. I usually buy cheap memory and not being limited by memory speed is a huge plus to me.