Using pc100 and pc133 at the same time..

[Guest]

I am running a p3, and I have a 256mb pc133 chip in it, I was just wondering if it is 'safe' to use a pc100 128mb chip along side it? Just curious as to the compatability of the two.

Thanks

 

[Arrow]

Depends. If your processor uses a 100mhz bus, you can downclock the PC133 DIMM to run at PC100 spec. Most of the time, mixing the two is not a problem. Unless your PC100 can do 133mhz, you'll have to downclock it. If you processor uses a 133mhz bus, you would probably still be able to run FSB:RAM at a 4:3 ratio.
But if you're thinking of buying... PC133 is cheaper most of the time nowadays anyway.

Rob
Please visit <b><A HREF="http://www.ncix.com/canada/index.cfm?affiliateid=319048" target="_new">http://www.ncix.com/canada/index.cfm?affiliateid=319048</A></b>

 

[Guest]

It is a pc133 bus, I was just wondering if there is anything I should be doing or if the entire system would then be running at the rate of the 100?

Thanks

 

[FatBurger]

Don't bother with it. PC133 and PC100 are the same price nowadays, and you don't want to overclock the PC100 or underclock the CPU and PC133.

------------------------------
Apple? Macintosh? What are these strange words you speak?

 

[Arrow]

As I said, you might be able to run your FSB:RAM at a 4:3 ratio. You should be able to find that option in your BIOS. Just because you're using PC100 RAM doesn't mean that you'll be underclocking your processor.

Rob
Please visit <b><A HREF="http://www.ncix.com/canada/index.cfm?affiliateid=319048" target="_new">http://www.ncix.com/canada/index.cfm?affiliateid=319048</A></b>

 

[Crashman]

They are compatable. If you use both you will have to set both at 100MHz. If your system can use memory at 133mhz I recommend ditching the PC100.

Cast not thine pearls before the swine

 

[Guest]

so just ditch the pc100 128mb? Would it decrease my computer speed and performance?

Thanks again...

 

[Guest]

Well, it is a tradeoff, with less RAM, your applications run a little slower but your PC133 RAM will be utilised to its maximum efficency (provided your mainboard supports 133 FSB).

Both RAM modules...it is the choice I will take cos more RAM is always better...speed isn't much of a performance factor. But if you have $$$, then purchase another PC133 RAM module.

-=$&| *WWWuuusssuuuppp?!?!?* |&%=-

 

[Crashman]

If you can use your memeory at the full 133MHz, then 128MB at 133 would run faster than 256MB at 100 for most applications. What speed processor and which motherboard do you have?

Cast not thine pearls before the swine

 

[Guest]

Using a p3 1ghz, not sure on the Mobo - I just got the computer from Dell (yes, I know, not exactly a computer hardward guru so I just purchased one...). The pc133 256mb came with the computer, and I already had the 128mb pc100 chip from my old comp.

I am 'newbie' when it comes to hardware, so if there are any specs or somethign that I should change, please provide directions

Thanks again everyone...

 

[Crashman]

In that case, no, you cannot use the PC100, it is too slow for the 133MHz FSB of the processor. Even if it was PC133, you would not see a noticable difference going from 256MB to 384MB.

Cast not thine pearls before the swine

 

[Guest]

I 'cant' use it? I have it in right now and the computer registers that there is 384mb ram...

 

[Guest]

I've been watching this thread and have a tangential (is that a word?) question:

Can I run a processor, say a 5x100 500MHz K6-2, at 100MHz FSB but allow the RAM to run at 133MHz FSB? Are there motherboards that allow this?

 

[Crashman]

How about "Can't use it PROPERLY". Some chipsets will allow you to run your FSB at 133 and your memory at 100. This will slow you down. This is most likely what happened in your case. I would try a good benchmark. With a 1000MHz processor, you may not notice that it is running slower, but it is. I would suggest 3D-Mark 2000. You will see significantly higher scores with 256 at 133 compared with 384 at 100.

Cast not thine pearls before the swine

 

[Guest]

I was always under the impression that if you mix PC133 with PC100, the PC133 will be limited to 100MHz by the PC100 stick...thus the slower performance...no?

Sample...

 

[Crashman]

It depends on several factors:
1.) If your memory is set at 100 instead of 133 in BIOS, it won't make a diference whether you use PC100 or PC133 as either will be operating at 100.
2.) If your CPU is a 100MHz FSB version and your chipset does not support a 100/133 split, your stuck at 100, see #1.
3.) Some motherboard support 100/133 CPU/Memeory bus (Asychronous). If you use PC100 autodetected, your memroy speed will be at the lower 100MHz speed. But you may be able to overclock it to 133 using manual settings
4.) If you are using a board that does NOT support Asychonous memory speed, with a 133FSB processor, you must either overclock the memory or underclock the processor.
5.) If you are using a motherboard that DOES support Asychronous memory speeds with a 133FSB processor, you will either have to run at 133/100 (slower), or manually set your memory to 133/133 (overclocking it).
Overclocking PC100 to 133 does not usually work. Sometimes it does.


Cast not thine pearls before the swine