Conflicts with PC100 and PC133 chips

Hey, wassup guys. I had a question. I have a Gigabyte P III motherboard with 2 memory slots which support both PC100
and PC133 chips. On one slot I got a 128 MB PC100 SDRAM module installed and the other one is currently empty. So I
was planning on buying a new 256 MB PC133 SDRAM chip
and install it on the empty slot. Ok the question is would
the new PC133 chip conflict or cause any problems with the
PC 100 one. And by the way, whats with the 100 and 133
thing. I never got to understand the difference between
them. I also would like to know which brands are good and
all. And by the way my processor is a Celeron 800 MHz,
FSB 100 and clock multiplier 8.

yeah you can put the pc133 stick in it but you wont run it at the stock 133MHz. this is the operating frequency the memory works and communicates with some other components in your machine eventually: the higher the faster.
youre not going to run it at the stock 133MHz because you have the other pc100 holding you back. then the pc133 stick will run at 100MHz, together with the pc100.



if you want them to run at 133MHz youll need to overclock the memory bus to 133MHz, which will push the pc100 operating frequency by 33MHz. this shouldnt be a problem but... if youre not planning to overclock the cpu either, youll need the proper frquency divisors in your mainboard: they will let you to run the system clock at 100MHz and the memory at 133MHz; otherwise youre going to overclock either the celeron to 1064MHz.

Ok so would it be better if I buy a 256 MB PC100 module instead?

And yeah, I aent into overclocking that much(in the sense of cooling that is). I can only increase the FSB to 124 MHz(Max)

i think you should consider going another way. you can buy 2 pc133 128MB instead. then if you will ever want to overclock your system, RAM will not be a problem; if your mainboard has the proper divisors to set the memory bus to 133MHz you will then get better overall performance than using the 384MB at 100MHz. anyway, if you not get it working at the 133MHz, performance difference between the 384MB and 256MB will not be so great in your case.

Thanks for those last replies.

Ok still I am confused. Unfortunately, currently I cannot offord to buy two new PC133 128 MB chips

Ok so know tommorow I'll be going to the market so what would you say. I have only two choice, either to buy a PC133 or a PC100 256 MB module. Like I said, its kind of hard for me to get the FSB to run at 133 MHz So what do you think. Like you said, if I put a new PC 133 module, it will run at 100 MHz so should I put a PC 100 module then. What I am trying to say is this

Suppose

----------------------------------------------

I buy a PC 133 Module

Its running at 100MHz because of the PC 100 chip on the other slot

And I got a PC 100 Module

Its running at 100MHz ( cuz its a PC 100 )

----------------------------------------------

Now the question is that would the PC 133 module give a lower performance cuz it was designed to run at 133 MHz or will it be giving the same performance as the PC 100 Module

I hope u understand what I am trying to say

Thanks again for your help

i thought the price between a 256 pc100 would be about the same as two 128 pc133. look at here, its not that great.

if you can afford two 128 pc133 that would be your best deal. if you can only get one 256 stick and youre not planning to overclock the system then there is no need for the pc133. it wouldnt lose performance because its made to work at 133MHz, it will work just as if it was a pc100 module.

oTTO, thanks for your help! Ok, I just went and bought it. A PC 133 256 MB chip

Suppose I had two PC 133 RAM modules, one of size 128MB and the other of 256 MB. Which one should I put on the first slot. Does it matter if I put the 128 MB first then the 256 MB or vice versa.

naif,


If they work reliably, then probably it does not make much of a difference performance-wise which you one put in what slot.

BUT, it is different in fact, so that if you have stability problems OR want to see the small difference in performance, you will have to try the different combinations.. because it depends on the SPD (preprogrammed) settings of both sticks ... which we can not guess from here. (the 128 could be a bit faster or slower than the 256 stick).

A good test is the sandra memory test... but be sure you always compare the same 'run' (i.e first run after boot).

Regards
FTC