Quote Originally Posted by lopri View Post
Yes, but because at that point the bottleneck is NB. It's my hypothesis that when NB is a bottleneck (i.e. NB frequency < 2 x memory frequency), higher memory frequencies are somewhat wasted. When you run Everest, keep an eye on memory read bandwidth and L3 read bandwidth. You will see both of them moving together very tightly. It seems to me, NB can only process as much as memory can feed it, and memory can send data only as fast as NB can process.

My hypothesis is in the post #27 and #28 in this thread. In your testing, if NB was clocked @2.8GHz, DDR3-1600/CL7 would be pulling ahead, leaving DDR2-1200 behind.

You can see it from Tony's first post in this thread. In the encoding test, look where the performance stops improving with DDR3-1333, yet keeps improving with DDR3-1600. It's somewhere around 2700~2800MHz NB. So DDR3-1333 is good enough to feed 2600MHz NB, but going higher you'll need a comparable (good timings) DDR3-1600 to keep the linear scaling.

So depending on applications - some apps will need to access system memory more often and others don't - NB frequency and memory frequency both matter, and ideally you'd want to have enough memory bandwidth for your NB even if some of it is wasted. If your NB doesn't clock any higher than, say, 2400MHz, then DDR2-1200 or DDR3-1333 will be all that's needed.
You are bang on the money here as it stands there is absolutely NO NEED to run 1600 ram 7-7-7-24 1t with any AM3 CPU at stock, even if AMD up the NB clock to 2.6GHZ you still would do better with 1333 6-6-6-24 1T.
Also remember i did these tests at 3.8GHZ, if i get time I will rerun them at stock 3.2GHZ to see where that pans out although i have a feeling it would be very close to the same.

Today I will run Elpida Hypers (cas 7 blade) at 6-6-6-24 1t 1600 just to see how this one performs and add a new graph.

Overall my conclusion from this testing to date is AMD need to drop 2000NB clock today and implement 2600mhz on BE. There is no need for them to leave it at 2000 and they would see nice gains in performance when compared to Intel CPU's. Regards where OCZ can help with this I have already asked for a 6-6-6- kit at 1600, I will now also ask for a 5-5-5-kit at 1333 for those not OCing as high but wanting the best at that lower clock.

Keep your eye on the Blade and platinum series for these kits