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E8400 bottlenecking with DDR2667 Memory?

J

Jarrstin

Limp Gawd
Joined
Jan 12, 2008
Messages
182
I just bought today one of the new Core 2 Duo E8400 3.0ghz 1333MHz Processors and a Gigabyte GA-P35-DS3L mainboard. Since this is costing a little bit of money, I was planning on waiting to rebuy new memory since I just upgraded my old system's memory to 4gb. I was wondering how much bottlenecking, overclocking, and/or problems I'm going to have running this new system with 4gb of DDR2 PC 5400 667mhz memory?
 
No problems at all.You're running it synchronized with memory. 1333 FSB = DC 667
 
That would actually be a problem when overclocking :)
Better to get 800 MHz memory or faster because these CPUs want to overclock very far, requiring fast memory.
I'd suggest getting fast valueram from Kingston or such. It's cheap and it overclocks well.
Latencies are no issues for Core2 CPUs anyway, because the cache buffers it all.
 
Yup, its fine if you're running stock, but it limits your overclock ability. Though, you should be able to OC those DDR2-667 sticks just a bit, if you needed to (just feed it more voltage and relax the timings).

/*------------- <cut n paste> -------------*/
Formulas for Intel platform @ 1:1 settings: (base FSB speed is SDR, or single data rate)
c × [Base FSB speed] = CPU Clock speed (c = CPU Multiplier)
2 × [Base FSB speed] = RAM speed (DDR: double data rate)
4 × [Base FSB speed] = Effective FSB speed (QDR: quad data rate)

On Intel platforms, running the RAM higher than a 1:1 ratio with the CPU is, for the most part, useless, so don't bother trying to do so. If the BIOS does it for you, just let it. All you need is a 1:1 config, though. Here's some possible clock speeds (as always with OC'ing, your results will vary):

E8400: 9 × 333 = 3.0Ghz, DDR2-667 << STOCK
E8400: 9 × 400 = 3.6Ghz, DDR2-800 << Nice OC
E8400: 9 × 445 = 4.0Ghz, DDR2-890 << Good OC
E8400: 9 × 500 = 4.5Ghz, DDR2-1000 << Great OC
E8400: 9 × 533 = 4.8Ghz, DDR2-1066 << WOW OC
/*------------- </cut n paste> -------------*/
 
Scali2 said:
That would actually be a problem when overclocking :)
Better to get 800 MHz memory or faster because these CPUs want to overclock very far, requiring fast memory.
I'd suggest getting fast valueram from Kingston or such. It's cheap and it overclocks well.
Latencies are no issues for Core2 CPUs anyway, because the cache buffers it all.
Click to expand...

No point in that.He already has 4GB.
All DDR2 667 memory can run DDR2 800 at CL5-5-5-12 1.9V.That means an OC from 3 to 3.6GHz for the CPU.That's an excellent way to use your existing memory.
 
savantu said:
No point in that.He already has 4GB.
All DDR2 667 memory can run DDR2 800 at CL5-5-5-12 1.9V.That means an OC from 3 to 3.6GHz for the CPU.That's an excellent way to use your existing memory.
Click to expand...

Probably. I personally use Kingston 667 5-5-5-15 valueram memory at 833 MHz 4-4-4-12 at 2.0v. Been perfectly stable for over a year now.
I run an E6600 at 3.0 GHz btw, so I have 1333 FSB like that... but the chipset is overclocked, hence the 'weird' 833 MHz.
 
Scali2 said:
Probably. I personally use Kingston 667 5-5-5-15 valueram memory at 833 MHz 4-4-4-12 at 2.0v. Been perfectly stable for over a year now.
I run an E6600 at 3.0 GHz btw, so I have 1333 FSB like that... but the chipset is overclocked, hence the 'weird' 833 MHz.
Click to expand...

So you're running the RAM higher than you need to (DRAM multiplier is at 1.25) -- that just causes more heat inside the case and doesnt yield much performance gain.
 
enginurd said:
So you're running the RAM higher than you need to (DRAM multiplier is at 1.25) -- that just causes more heat inside the case and doesnt yield much performance gain.
Click to expand...

No I'm not.
DDR2 isn't very efficient. The command rate is rather low. This means that you can't reach the theoretical maximum bandwidth in most cases. Running it at 833 MHz gives me more effective bandwidth than 667. I don't accidentally run it at this speed ofcourse. I tested both this setting, and 667 MHz with lower latencies... This turns out to be the best overall solution.

People who think FSB and memory need to run 1:1 live in the past.
 
Scali2 said:
No I'm not.
DDR2 isn't very efficient. The command rate is rather low. This means that you can't reach the theoretical maximum bandwidth in most cases. Running it at 833 MHz gives me more effective bandwidth than 667. I don't accidentally run it at this speed ofcourse. I tested both this setting, and 667 MHz with lower latencies... This turns out to be the best overall solution.

People who think FSB and memory need to run 1:1 live in the past.
Click to expand...

But the bandwidth increase isn't enough to warrant the more voltage and heat output, IMO, since Intel systems' performance increase doesn't scale well in terms of memory bandwidth. A system at 3Ghz and DDR2-667 isn't much slower than a system at 3Ghz and DDR2-833 - in fact, its probably less than 2% slower. I'm not saying they need to run 1:1... I'm saying that the system won't take enough advantage of it running higher than 1:1, so theres really no point to. All you need is a 1:1... you just want more.

This is a subjective matter... if you feel your system is that much faster, then by all means, go for it -- its your system, lol. After all, this is [H]... and people here tend to want to squeeze every last bit of performance out of their components. Personally... I'm a bit lazy in that regard... if the performance difference isn't enough to warrant my time and effort, I won't bother with it.
 
enginurd said:
But the bandwidth increase isn't enough to warrant the more voltage and heat output, IMO
Click to expand...

There is no way you can judge that, because you have no idea how hot my memory gets, and what kind of cooling I'm using etc.
Apparently, IMO it's worth it, and you don't know enough facts to form an opinion about my system.

enginurd said:
since Intel systems' performance increase doesn't scale well in terms of memory bandwidth. A system at 3Ghz and DDR2-667 isn't much slower than a system at 3Ghz and DDR2-833 - in fact, its probably less than 2% slower. I'm not saying they need to run 1:1... I'm saying that the system won't take enough advantage of it running higher than 1:1, so theres really no point to.
Click to expand...

Depends on what you're doing with your PC, doesn't it? Since you don't know what I do with my PC, you again don't know enough facts to form an opinion on the matter.
I'll give you this though:
What if my system runs 2% hotter, with 2% more performance... still don't think it's worth it?
 
Scali2 said:
There is no way you can judge that, because you have no idea how hot my memory gets, and what kind of cooling I'm using etc.
Apparently, IMO it's worth it, and you don't know enough facts to form an opinion about my system.
Click to expand...

More voltage to the RAM = more heat from the RAM. Whether you cool your system well or whether your sticks manage heat better than others won't change that fact.

Scali2 said:
Depends on what you're doing with your PC, doesn't it? Since you don't know what I do with my PC, you again don't know enough facts to form an opinion on the matter.
I'll give you this though:
What if my system runs 2% hotter, with 2% more performance... still don't think it's worth it?
Click to expand...

Regardless of what you do with your system, I'm merely pointing out that, contrary to common believe around here, Intel systems don't take that much advantage of running the RAM at a higher than 1:1 ratio. Whether "that much" is worth it or not is entirely up to the user; So... in my own opinion, its not worth it... for anyone, even you. Obviously, you think its worth it... and thats fine. I'm just letting everyone know what I think. ;)
 
enginurd said:
More voltage to the RAM = more heat from the RAM. Whether you cool your system well or whether your sticks manage heat better than others won't change that fact.
Click to expand...

Yes, but you don't know how much more heat is produced by the ram, and how that compares to the heat produced by the rest of the system. For all you know, it's negligible.

enginurd said:
Regardless of what you do with your system, I'm merely pointing out that, contrary to common believe around here, Intel systems don't take that much advantage of running the RAM at a higher than 1:1 ratio. Whether "that much" is worth it or not is entirely up to the user; So... in my own opinion, its not worth it... for anyone, even you. Obviously, you think its worth it... and thats fine. I'm just letting everyone know what I think. ;)
Click to expand...

You're saying it's pointless, I'm saying that I have a point.
 
Ok, we're going in circles. :p

You're saying that little bit of performance is worth it, and I'm saying its not. Simple as that. We're done. Have a good weekend!

EDIT: You're saying that little bit of performance is worth it, depending on what you do with your system and the heat output of the RAM. I'm saying its not worth it, regardless of either of those.
 
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