[JohnQ]

Hello, I have a PIII 500MHz Compaq with a 100MHZ Front Side Bus. My cousin gave me two 128MB SDRAM DIMM's. I searched their part numbers on the internet and most sites told me they were PC66 (a handful of sites listed them as PC100). Now I have no idea how to find out their speeds. I just wanted to know:

Q1) If I install one of the chips (assume it's PC66 128MB) in a computer that already has a PC100 64MB DIMM, will my computer's speed slow down? Will I have an appreciable decrease in RAM/computer performance?

Somewhere I read that 66MHz chips can work at a max speed of 112MHz.

Q2) Is there a program that will tell me the speed my RAM is running at?

Q3) What is better: Having 64MB of PC100 RAM in my system or 256MB of PC66 RAM?

I appreciate any help you could give me, Thanks!

 

[rmay635703]

Q1) If I install one of the chips (assume it's PC66 128MB) in a computer that already has a PC100 64MB DIMM, will my computer's speed slow down? Will I have an appreciable decrease in RAM/computer performance?

->I have run PC66 chips at 100mhz and 133mhz FSB BUT

Remember that this isn't guaranteed, the only sure way would be to install the chips then run memtest86 and see if they pass.

Otherwise look at the chips on the module, generally chips with a -10 -9 -8 at the end can usually run at a 100mhz fsb at CLK3.

If your chips say -12 -15 or -20 they probably won't run at a 100mhz FSB and if they do you are overclocking them.


Q2) Is there a program that will tell me the speed my RAM is running at?

Yes, Aida among others


Q3) What is better: Having 64MB of PC100 RAM in my system or 256MB of PC66 RAM?

256mb of PC66 is better than 64mb of PC100 (unless your still on windows 95 then the performance boost is questionable)

Cheers

 

[JohnQ]

Thanks for the quick response. I tried the RAM in one of my computers and it didn't work. I'll try it in my other computer today and see what happens. That memory speed testing software you recommended should be a big help!

 

[rmay635703]

Post the chip number off the modules black chips (its sometimes hard to read)

I will tell you what it is, its possible that you have EDO or Fast page, which won't work.

Good Luck

 

[JohnQ]

Here are the ID numbers for my two RAM chips:

Toshiba (9 black chips on each side)

==> TC59S6408BFT-10


SEC (9 black chips on each side)

This second one is a bit tricky because the 9 black chips all have this number:
==> KM48S8030BT-G10

BUT there's also an original SEC factory sticker that says:

==> KMM374S1623BTL-G0

 

[rmay635703]

Sorry about the wait, those are indeed 128mb but...

Since they have an ODD number of chips you have ECC sdram

ECC will not always work in a normal motherboard
(even though it should regardless)

ECC does work in many servers and high end workstations and it should sell on ebay (for example) for more than a normal 128mb pc100 sdram dimm.

Another problem (even if your mobo would recognize it) is that at least one of the modules is CAS 3, CAS 3 PC66 modules are less likely to operate at PC100 speeds reliably than CAS2 (which is almost guaranteed to operate pc100 CAS3)

Good Luck

 

[JohnQ]

Thanks for all the help!

 

[~Candy~]

John, I see you reported this as solved....did any of the chips work for you??