Corsair Dominator 2x2GB PC8500 DDR2

[geok1ng]

http://www.anandtech.com/mb/showdoc.aspx?i=3208&p=9
Moving on to the analysis at 450Mhz FSB, although we are able to show impressive memory read speeds at this same bus frequency using a 3:2 divider for DDR2-1350 CAS 5 at a tRD of 5, this configuration was far from stable on stock cooling alone - as was the memory speed. Most likely, the need to loosen tRD to 6 will be inevitable at this bus speed. Right from the start, we can see that TRD takes a hit as our minimum values thus far came at the lower 400Mhz FSB. What's more, possible memory configurations at this FSB do not seem to offer any real improvement over those at 400MHz. The first option worth considering, DDR2-900 at CAS 4, can be a little slow, especially considering that a tRD of 6 is not allowed. The DDR2-1200 choice will provide (at best) only miniscule gains over the same memory speed at 400MHz FSB because of the additional throughput efficiency made possible by the higher bus speed. Then again, the increase in TRD to 13.3ns, up from the minimum value of 12.5ns at 400MHz FSB, may completely negate any chance of a performance gain. Our last contender, DDR2-1080 at CAS 4, might be another neutral choice - on one hand there could be a small gain in performance over DDR2-1000 (CAS 4) seen at 400MHz FSB, but again the higher TRD may be this configuration's undoing.

In the end we decided to run our Intel Core 2 Extreme QX9650 at a final FSB of 400MHz with a multiplier of 10.0x at an even 4GHz. Our 4x1GB of OCZ DDR2 PC2-8000 Platinum Extreme Edition memory was set to run at DDR2-1000 (5:4) CAS 4 with a tRD of 5. Ultimately, the ASUS Rampage Formula provided us the ability to build a well-tuned system. Without question, ASUS' addition of BIOS options for direct tRD manipulation was instrumental to our successful overclock. When paired with top-end GPUs from either ATI or NVIDIA, our rig becomes a formidable gaming platform for enjoying today's titles and beyond.

i recommend people to read the whole article in order to better understand the benefits of using a tRD of 5 when overcloking DDR2 plataforms- there had been numerous reports that other chipsets do NOT obey the Anandtech's formula for allowed tRDs: so 1:1 operation at tRD 5 with speeds of 400Mhz FSB is a goal.

Moving to tRD of 6 AT suggests When viewed together the task of picking out a couple of the best choices becomes rather simple. A+ ratings, of course, go to the two configurations colored in light green (5:4 for DDR2-1000 CAS4 and 3:2 for DDR2-1200 CAS 5). You may be surprised, as we mentioned earlier, that they both use a humble 400MHz bus speed. If forced to choose another option, close second place awards might go to 450Mhz FSB - 1:1 and DDR2-900 CAS 4, or 4:3 DDR2-1200 CAS 5 (assuming your motherboard is capable of stable operation with the sometimes poorly implemented 4:3 divider). Just do not forget - whatever memory option you choose, be sure to remember the importance of tRD.



So a quick pathway for memory tweaking is:find stable voltages operations FSB 400 1:1 divider tRD of 5> increased FSB until tRD of 5 is no longer possible/stable> record results at this setting> move to tRd 6 CAS 5 and try 1:1/6:5/5:4 and 4/3 operation-whichever is best will keep the same FSB step increasing until the CPU is running closer/at the 24/7 frequency goal.