AM3 CPU + 1600 MHz RAM = Uh oh..?

[erocker]

With Deneb's, stepping matters also. C2 = not so good, C3 = better. My 965BE C3 can run 1600mhz cas 6 with a 2750mhz NB. Anything after 2750mhz it requires too many volts or I have to reduce RAM frequency. My 1100T can do 1600 cas 6 with 3200mhz on the NB at 1.3v. Results vary from chip to chip. If xsever has a c3 stepping chip, I would try for 1400mhz on the RAM with cl6 or 7 and 2800mhz NB would give optimal performance.

 

[xsever]

If xsever has a c3 stepping chip, I would try for 1400mhz on the RAM with cl6 or 7 and 2800mhz NB.

I'll keep that in mind, but if I were going to go with 1400, I might as well stick to 1333, which is standard, and then focus on timings instead of voltage and NB.

 

[erocker]

I'll keep that in mind, but if I were going to go with 1400, I might as well stick to 1333, which is standard, and then focus on timings instead of voltage and NB.

Without focusing on your NB, all the rest is useless. NB directly affects it all.

 

[xsever]

Without focusing on your NB, all the rest is useless. NB directly affects it all.

If I change my 1600 RAM's speed in BIOS to 1333 and use 1333 timings, would I still need to modify the NB to accommodate this "underclocking"?

 

[erocker]

If I change my 1600 RAM's speed in BIOS to 1333 and use 1333 timings, would I still need to modify the NB to accommodate this "underclocking"?

For maximum benefit, yes. Just set it to 2600mhz 1.25v. (It's all perfectly safe and well within AMD specifications.)

 

[xsever]

For maximum benefit, yes. Just set it to 2600mhz 1.25v. (It's all perfectly safe and well within AMD specifications.)

I'll go with that and start fine-tuning as I progress. So this should be better than running the memory controller of the 955 at 1600?

I mean if there is no harm to the CPU, I would rather run the RAM at their full speed.

 

[erocker]

I'll go with that and start fine-tuning as I progress. So this should be better than running the memory controller of the 955 at 1600?

I mean if there is no harm to the CPU, I would rather run the RAM at their full speed.

The memory controller is actually the NB. It doesn't make much sense to run the RAM at full speed if you're not going to get any performance out of it. AMD likes lower timings as opposed to a higher frequency.

 

[xsever]

The memory controller is actually the NB. It doesn't make much sense to run the RAM at full speed if you're not going to get any performance out of it. AMD likes lower timings as opposed to a higher frequency.

NOTED. We can then conclude that 1333 & tight timings > 1600 & regular timings.

Thank you!

 

[erocker]

NOTED. We can then conclude that 1333 & tight timings > 1600 & regular timings.

Thank you!

Absolutely!

 

[xsever]

Absolutely!

I benchmarked 1333 with tight timings vs 1600 with stock 9-9-9-24 and the 1600 configuration beats the 1333 one in both bandwidths and latency.

Care to comment? Am I missing something?

 

[Pestilence]

Those are some dismal memory benchmark figures

 

[xsever]

Those are some dismal memory benchmark figures

Done using AIDA64 Memory Benchmark Tool.

RAM/Timings Read Write Copy Latency
1333 7-7-7-21 8945 7484 11248 50.1
1600 9-9-9-24 9095 7486 11524 49.5

 

[erocker]

I benchmarked 1333 with tight timings vs 1600 with stock 9-9-9-24 and the 1600 configuration beats the 1333 one in both bandwidths and latency.

Care to comment? Am I missing something?

Strange. All the testing I've done and others have done say otherwise. Honestly, go with whatever works best for you. What is your CPU/NB frequency set at? Based off of the post above me, you need to increase the CPU/NB frequency.

Those are some dismal memory benchmark figures

What are you speaking of? Where are these figures?

 

[xsever]

What is your CPU/NB frequency set at?

Currently at 2200.

 

[erocker]

Try getting it to at least 2600mhz. I'm not sure if your chip is a C2 or C3 stepping though. You can check that in CPU-Z.

 

[xsever]

Try getting it to at least 2600mhz. I'm not sure if your chip is a C2 or C3 stepping though. You can check that in CPU-Z.

My CPU is a C3 as confirmed by CPU-Z. If I were to overclock the NB further, wouldn't the gain of 1600 over 1333 remain relatively the same? I am trying to stay away from overclocking the CPU/NB and 1600 seems to be a better performer in that case.

I am open for tips though.

 

[erocker]

My CPU is a C3 as confirmed by CPU-Z. If I were to overclock the NB further, wouldn't the gain of 1600 over 1333 remain relatively the same? I am trying to stay away from overclocking the CPU/NB and 1600 seems to be a better performer in that case.

I am open for tips though.

The CPU/NB is still bottlenecking the system.

 

[xsever]

The CPU/NB is still bottlenecking the system.

So you're saying raise the NB and achieve better timings with 1600? What are the safe limits for the NB?

 

[erocker]

So you're saying raise the NB and achieve better timings with 1600? What are the safe limits for the NB?

Keep it under 1.35v and watch CPU temps. I gave the screenshot to show what a high CPU/NB can do. Pay no attention to my RAM.

Try for 2600mhz. I can achieve that on my 720 x3.... which I'm trying to get running again...

 

[xsever]

Keep it under 1.35v and watch CPU temps. I gave the screenshot to show what a high CPU/NB can do. Pay no attention to my RAM.

I'll test and see how much performance gain there is and then decide whether it's worth it or not.

Thanks again.

 

[xsever]

How do you personally test the stability of timings? By stress testing the CPU using prime95 and such?

 

[erocker]

How do you personally test the stability of timings? By stress testing the CPU using prime95 and such?

Most use Memtest, as do I however I find that playing any Source engine game really loves to let you know if your RAM is stable or not. It's more fun that way.

 

[Hayder_Master]

WTF, i pass 1600mhz with gigabyte mother board

 

[xsever]

WTF, i pass 1600mhz with gigabyte mother board

Why so?

 

[scaminatrix]

I hit 1933mhz C9-9-9 with my old RAM (2x2GB OCZ Reaper HPC 1600 C7) with my gammy un-unlockable 555 BE and C4F if it's relevant (see specs).