Can I install PC100 sdram memory in my computer if I already have PC133 intalled ?

Question

Hi,

I want to upgrade my computer by adding SDRAM dimms. Actually I have one SDRAM 256Mb PC133 in it and I want to know if I can add two SDRAM 512Mb PC100 in the empty slots ?

Can I combine two different (PC100 and PC133) and if not, can I replace the PC133 by the two PC100 and what would be the impact of doing that ?

Thanks

Answer 1

First, to answer your question, Yes, but you do not want to.
Reason: PC133 operates @ 7.5 ns, 133 MHz actual speed, while PC100 operates @ 8 ns, 125 MHz actual speed. In other words, the PC133 is considerably faster response.
> If you combine both, PC100 and PC133 memory, the mother board will respond to the PC100 speed pulling down the PC133 to equal it. You can replace the PC133 you now have with the (2) PC100 SDRAM but you will not notice that much better performance. Memory is not expensive. Suggest you buy a new SDRAM 512 Mb of PC133, put the new memory into slot 1 and move the 256 Mb to slot 2. Be Sure Your Processor can support that much memory. If you have a newer computer then you probably will not have any trouble. Your computer will address slot 1 then go to slot 2. BE SURE YOU ARE STATIC DISCHARGED BEFORE ADDING YOUR NEW MEMORY AND MOVING YOUR 256 Mb to Slot 2. If not - You can do a Lot of Damage including wiping out your new memory. Good Luck

Answer 2

That has to be a P3 system most only handle 384 or 512 ram so any more wont be recognized. PC100 and PC 133 will work together most of the time but at the slowest speed PC100 when you mix it. You need to check the specs of the motherboard see what the max amount of memory it can handle, while inside change the battery cr2032 walmart. Try ebay for pc133 as no one uses it anymore so it is really cheap as you will reduce the speed of the memory by 33% if you mix it with pc100

Answer 3

While the RAM will fit in the memory slot, mixing speeds will more than likely prevent you from being able to boot up. Sorry!

The implication of using two PC-100 chips instead of one PC-133 is that you will have more memory than before at a slightly slower speed. Acutally, the speed difference is negligible and the added RAM is a benefit.

Assuming that you're going to buy additional, faster memory, you will find that RAM is fairly cheap these days. I recommend that you do not buy from the PC manufacturer because his price will be twice the after market vendors. Instead, use Kingston, SimpleTech or another of the better manufacturers so that you get the right modules and do not have to ship it back.

One last thing... be sure up upgrade/flash your BIOS. Many times this is required for your PC to see all the memory and sometimes, to be able to boot.

Good luck,
EC

Answer 4

yes you can if your mother board can handle that type of ram (PC100) .. BUT !!! it will cause the faster 133ram to slow to the slower 100rams speed...
if you replace it all round with the 2 100rams it will be slower ram, But i dont think it will be a noticeable difference in speed... Also it depends on how much ram your MoBo can handle too! So I would say the more ram the better as long as the MoBo handles the amount you put in. and I dont think the slower speed difference will matter seeings you have now put in more ram. Because it will all balance out... Good Luck

Answer 5

Maybe.

First, not all motherboards support 512 MB chips... so they may simply not be recognized OR they may be recognized only as 256MB chips.

Your motherboard may limit the maximum RAM your PC can use - you may max out at 512, 768, or 1024 MB.

If your existing CPU operates on a 133 MHz bus, then you could create serious system instability.

Further, NEWER chips are NOT all backward compatible.

So, should you do this? Probably not. Go buy appropriate RAM for your computer based on the brand of computer or the make/model of the motherboard. For example, provide that information on www.crucial.com or www.kingston.com and you'll get the correct memory you need.

Answer 6

yes you can but then the system automatically adjusts the ram speed to PC100 which is slower than PC133 (on both sticks)

Answer 7

While you can do this and the 133 ram will slow to 100 in order to accomodate the slower ram, you need to check if your motherboard will support that much ram in the first place. Many motherboards that support 133 ram may not have memory addressing capabilities above a gigabyte and some may be even less!

Answer 8

you may desire to no longer use the stick of RAM. Such RAM is typically BACKWARD nicely suited yet no longer forward nicely suited. Use a PC133 in a PC100 equipment... do no longer use a PC100 in a PC133 equipment. Pentium III 866 chips run at 133 MHz - the RAM must be waiting to do the comparable.

Answer 9

ram is tricky you may want to consult the manufacturer of the computer before doing this