mixing pc-100 & pc-133 ram

Hello all,

When mixing pc-100 and pc-133 ram, is there any certain order I should install them. For example should I install the pc-133 or pc-100 in the first slot, or does it even matter.


Thanks

 

Just try it. They may not work at all and then again everything may be fine. The overall speed will be the lower of the two. That's if they work!

 

Hi.

PC100 and PC133 will run just fine together. Install them in any order. The 100 and 133 refer to the FSB (Front Side Buss) speed. If you are running a CPU that requires 133 or higher FSB then the PC100 may not work at all. If that is the case you might can go into the BIOS on bootup and change the CAS from 2 to 3 and it might work fine. Most memory have a pretty wide margin and most PC100 will run great at 133 FSB at CAS-2. If not, run it at CAS-3. The time difference between CAS-2 and CAS-3 in a years time amounts to about the time span of a quality hiccup. If you have trouble with the PC100, try and sell it and get a PC133. You should be able to swap out for less than $10.00. Lots of people out there are looking for PC100.

Consider this. Whenever I add or change memory or shift a stick of memory to another slot I always boot from a floppy and run a memory checker. Other than an initial check of the hard disk, the system leaves the hard disk alone. That way if the memory is bad it won't read and write bad data on my hard drive and mess up my windows and other program installations. There are a number of memory checker programs out there and most are free. You just need a boot floppy and then write the memory checker on that floppy. Sometimes you have to set the bios to boot from the floppy rather than the hard disk. Always be sure the system is booting from the floppy before changing or inserting a new memory stick. This way your system can't get messed up by an askew insert of a memory stick or a bad stick of memory.

 

hehehe ...... Hiccups can kill ya. Ever heard of the kind that don't or won't go away?

"most PC100 will run great at 133 FSB at CAS-2 "

Oh yea? Let me know where you are getting that stuff ....

 

Couldn't leave this one alone.

Yes, it can make a big difference as to what you install in which slot. Some MB's won't recognize a larger SDRAM module if a smaller module is in slot 0, even if they are compatable. Are they the same size re: mb? Also, many MB's that require CAS 2 won't even recognize CAS 3. Also, what is the chip configuration - big potential conflict here.

SDRAM should be backwards compatable, but I've seen cases where its not - usually has to do with actual chip configuration and MB restrictions.

Still would like to get that PC100 that runs at 133 CAS2. Me and a few million others !!!!

 

That's absolutely correct. If you get a cheap motherboard and $19.95 memory from the local department store you'll run into just about anything. You can overclock memory chips just like a cpu. I ran a total of 512 PC66 in an Abit at 100 FSB with the cpu overclocked to 947 MHz for about a year. I had the CAS set to 3 and it ran just great without any problem whatsover. I didn't start out to overclock the memory chips. Just didn't want to buy more when I had those. You can do the same with PC100 at 133 FSB. There are many PC133 sticks running above 150 FSB. They usually have a pretty good tolerance to work with. A lot of the computers I've built over the years get upgraded to a faster cpu but the owners just didn't want to spend the money for new memory (when memory was very expensive). Just went to CAS-3 and no problems at all. Out of about 400 sticks I only ran into problems on 2 or 3.

It's best to run a memory checker that will write a pattern into memory and let it sit there for a couple of hours before it checks what it wrote. If it gets past those checks, the memory will run all the time just fine.

If JMark's asking a question about PC100 and PC133 then there is a high probability that his system is running at 100 FSB (or even 66) and the PC133 is the newer stick of memory. If that is the case then he has no problem. That memory mix should run fine. He can check the memory without endangering his hard drive by booting from a floppy and checking. Mix it and test it. That's how you find out. It is not a question if the PC133 will work, it's only a question of if the PC100 will work.