Please clarify: Can pc133 RAM be used as pc100?

[aulendil]

My situation is as follows. I am running a K6-2 450 in an ASUS P5A with a FSB of 100MHz, and I am currently using 2 64MB pc100 DIMMs. I want to add a 128MB Kingston stick, for a total of 256MB. It will be cheaper for me to buy the pc133, but will it work as and with the pc100s that I currently have in the board.

I have been trying to get a straight answer all evening from countless pages that I have read, but it still isn't clear to me. I would like to use the pc133 if I could, as it is cheaper, and because I would be able to transfer it to another machine in the future that may require pc133.

Any and all advice is greatly appreciated.

 

[DeathroweR]

Some motherboards may not allow it; but on others it can be used even as PC66 with no problem.

 

[jsbush]

The ram will run at the speed you tell it to run. All PC-133 meens is that it is garanted to run at 133mhz .

 

[aulendil]

Since I would be mixing pc100 and pc133 sticks, would the pc133 default to pc100, as the FSB is set to 100MHz? Or would I have to set a jumper somewhere?

 

[Quickfingerz]

yes it can. it can also do PC66

 

[jeremy806]

Listen here dude. SDRAM DIMMS, for the most part, are SDRAM DIMMS.

Like the other fella said, PC-66, PC-100, PC-133 are just rated speeds. That is, PC-66 will work on a bus speed of upto 66, PC-100 will work on a bus speed of upto 100, PC-133 will work on a bus speed of upto 133. Overclocking memory means running memory above rated speed.

Solution: If you buy any memory right now, buy PC-133 so that if you need it later, after a system upgrade, it may still be useable.

And, no, there is not any jumper or setting, just plug it in.

Jeremy

 

[etech]

Crucial says it will work. Notice they are selling both PC100 and PC133 for your motherboard.

Most but not all motherboards will work.


I'm running two 128meg PC133 sticks on my BH-6 at 100Mhz.

 

[prodigall]

I am running a single Infineon 128meg PC133 cas3 stick at 100mhz cas2 with my k62 450 no problems. But I have not tried a combination with any other memory sticks.

 

[Boogak]

Yup it should work. The PCXXX rating is just the recommended max speed of the RAM, if you will. I have a PC100 and a PC133 DIMM running on the same machine.

 

[Pauli]

There is a great deal of confusion on this subject. Once you realize that the memory sticks themselves do not contain any clock generator, you will understand much better. The clock on the motherboard is what "drives" the memory - the memory runs from this clock generator. Thus, the memory is rated at what its maximum capability is. Of course, us overclockers try to push the sticks beyond the rated speed. How do we do it? By raising the FSB clock speed on the motherboard, of course. I hope this explanation helps...

 

[chuckieland]

indeed, indeed

 

[Atroz]

HI,

I've got a friend with a K6-2 500 on a P5A with a mixture of PC100 and PC133 RAM totalling 196 Megs. I think it's one stick of 64M of PC100 and 2 of 64M of PC133. Seems to be working just fine for him.

 

[zippy]

SDRAM is SDRAM- the only thing that sets them apart is their rating. 8ns generally implies PC100 (though 8ns=124MHz really...so should it be PC124? No, it would confuse people ), 10ns generally implies PC66, 7.5ns genarally implies PC133, 6ns generally implies PC150.

PC133 can work at 100MHz bus just fine.

 

[Burn]

Just make sure you purchase the correct memory. Contrary to popular opinion not all PC133 will work on motherboards that work with PC100 or PC66. Some older boards will not work with PC133. For confirmation just do a search on Pricewatch for confirmation. You mention buying kingston, sounds good.