Memory timing questions

[Staz]

When I see good memory listed, it's usually 4 numbers, A-B-C-D where A is the CAS level. I know B and C should be in the 2-3 range with 2 being better(faster). My question is on D. I always thought the lower the number, the better. However, I see a lot of people running D higher. For example, I see 2-2-2-11 as a popular timing. Could someone explain to me what D is and why I see people running it at higher than expected numbers?

 

[gamerj]

the fourth number is the "min RAS active Time (tras)" (i think) and i have no idea what that means or does...
I do know that timing your memory is a rather delicate question...
All those numbers relate to- and effect eachother, and timing them in such a way your system is happy with them is more of a trial and error thing than a given. At least for 90% of the clockers out there..

So in short i really have no idea lol

p.s.: If you have an amd64 system u could download the "A64 Tweaker" .... with that u can (carefully) experiment with the timings...

 

[LED]

D as you refered to is the tRAS timing which is the Active to precharge delay and is not at all that important. NForce in general like it high whereas Intel seem to prefer a little lower but not in all cases...no matter as it is rarely used because most mem timings are constant and tRAS would be call on if timings are somewhat unbalance and a new need is called for such as opening a new application

 

[Staz]

My Hyper-X defaults to 3-3-3-8. On my Nforce2 mobo, I want take the first 3 options to 2-2-2, but not sure if I should leave the 4th one at 8, or jump it to 11. Thoughts?

 

[LED]

Leave it @ default and if it doesn't work then jump to 11...figure 3 cylces on an active to precharge is pretty much meaningless in performance.