Refresh my memory about RAM latency

[purecomedy]

I have an old 1 Ghz Celeron running with an FSB of 100 Mhz. Even if I run PC-133 RAM it will only run at 100 Mhz and effectively be exactly the same as PC-100 RAM is my understanding.

If I have PC-133 ram with a latency of CAS 2 vs. PC-100 RAM with a CAS latency 2 they be the exact same speed right?

I guess my point is, whether it is PC-100 or PC-133 RAM I would always prefer ram with a CAS latency of 2, rather than CAS latency of 3. The 100 vs. the 133 becomes irrelevant because the FSB forces the RAM to run at 100.

[YARDofSTUF]

If your limited to 100mhz because of the FSB then yes latency is the only speed factor to worry about.

Some motherboards had the fsb+ pciclk option to allow the RAM to run at 133 while the fsb stayed at 100 as well.

[purecomedy]

If your limited to 100mhz because of the FSB then yes latency is the only speed factor to worry about.

Some motherboards had the fsb+ pciclk option to allow the RAM to run at 133 while the fsb stayed at 100 as well.

Well my motherboard on the machine using this memory is an ASUS P3B-F, to my knowledge it is limited too 100 Mhz FSB. If you know quickly how to find out if the RAM can run out at 133 Mhz let me know.

All I am thinking with this machine is that it has 512 MB of RAM right now (CAS 3), XP runs so much better with 1 GB. If I could upgrade this for like $10 by buying some used memory I certainly would and as an additional detail I would try to get CAS 2 RAM.

I have heard the story both ways.....That I'll notice a huge difference using RAM with CAS latency of 2 and other people saying I won't even notice.

[YARDofSTUF]

If you have cas 3 now, and it cant run at 2, then you will have to replace the ram with all cas2 ram. The cas 3 RAM MAY run at cas 2.5, you should try it. The fsb+pci clk option would be in the memory section, advanced section, or cpu frequency section of the bios.

Difference from cas 3 to 2, ya there would be a difference.

[purecomedy]

If you have cas 3 now, and it cant run at 2, then you will have to replace the ram with all cas2 ram. The cas 3 RAM MAY run at cas 2.5, you should try it. The fsb+pci clk option would be in the memory section, advanced section, or cpu frequency section of the bios.

Difference from cas 3 to 2, ya there would be a difference.

If I try to push the RAM too hard will it just cause the computer to be unstable or is there a substantial risk of it frying the RAM?

[Brent]

if you give it too much voltage you can damage it

there honestly isn't that big of a difference between cas 2 and 3 in real world apps, for gaming you won't notice a difference

the difference however would be 'benchmarkably' noticable

if you can get cas 2 go for it, if it is cheaper to go cas 3 and higher capacity, i'd go that route, i'd rather have 1 GB of cas 3 than 512mb of cas 2

[purecomedy]

Doesn't look like my motherboard will support CAS latency 2.5. Unless there's a special trick to getting that option to appear in BIOS?