PC66 work in KT133a chipset?

[DougK62]

Here's the situation. My buddy has a P3 500mhz in a supermicro slot1 board that we are going to upgrade. I've ordered an MSI K7T Turbo2 board and Duron 1.2 to do this. His old slot1 board uses SDRAM, but I don't know what flavor it is (he lives quite a ways from me and is not computer literate). So my question is this - if a stick or two of his memory (512 total he has) is a measly PC66, will it still "work" in the new KT133a board? Obviously it wouldn't perform like it could and we're hoping it's all at least PC100, but we're on a budget and just want it to work. Your thoughts? TIA.

Douglas

 

[Boonesmi]

the only way a pc66 stick would work is if its capable of running 100mhz (some sticks can overclock that high, some cant)

but... even if it will run on the 100mhz bus the kt133a can only run the ram at 100mhz if the fsb is 100mhz. this means you would have to use a duron or an older athlon, otherwise the fsb/ram will be 133mhz (and i really really doubt you have any pc66 ram that can clock that high)



edit.... as a side note you said "Obviously it wouldn't perform like it could" but if the pc66 ram will run stable on the 100mhz bus then the performance will be identical to a stick of pc100 (cause in effect your making the pc66 perform at pc100 speed)

just to clarify pc66 can't run on a kt133a board and still run at its designed speed

 

[DougK62]

I think I may have eased my mind about the situation Since the SDRAM is coming from a P3 500 Slot1 it would HAVE to all be PC100 because the P3 has a 100mhz FSB, right? How could I have missed that? It must be too late for me - time for sleep

Douglas

 

[MoMeanMugs]

It looks like Boonesmi needs to hit the books again. You can run your FSB independently of your RAM speed.

 

[Boonesmi]

true the memory can run asynchronous from the fsb on the kt133a chipset, but... only in one instance, thats when the fsb is 100mhz and the ram can be set to run at either 100mhz or 133mhz (ie ram = fsb, or ram = fsb+pci)

but you cant run a 133mhz fsb with 100mhz ram on the kt133a chipset.... which he would need to do if he wanted to use his current ram with a newer athlon

 

[Peter]

OK, here's the scoop.

That P-III 500 runs on 100 MHz CPU bus for sure. Depending on what chipset you have, the RAM can run at 66, 100 or 133 MHz. E.g. VIA P6 chipsets can run the RAM at 33 MHz lower or higher, or exactly at CPU bus speed.

VIA and SiS Athlon chipsets however can only run the RAM at CPU speed or 33 MHz higher.

So you need to check what kind of RAM you have there. If it's 100 MHz RAM, then you need to get a 100 MHz bus CPU (a Duron or a 100 MHz bus Athlon), if it's 133 your CPU choice is unlimited, and if it's 66 MHz RAM then plain forget it.

regards, Peter