pc100 and pc133 compatability

[athlonfan]

If I put pc100 and pc133 in a motherboard, the Asus A7V for example, would I be able to run the 100 at 100 and the 133 at 133? Also if some was cas2 and some was cas3 could I run the cas2 at cas2 and the cas3 at cas3? Is there a chance that pc100 might not run in an athlon, in other words does it matter what type of processor I use? Finally is 8ns an exceptable rate for pc133? Thank You

[canit]

You can try overclocking the PC100 to 133Mhz or underclock the PC133 to 100Mhz(you can't set their frequency seperately- at least on my motherboard). On my socket A board I can set the DRAM timing(normal, fast, and turbo) of each bank independently, but not the cycle length(CL2 or CL3).

[gogogo5]

I have an Asus A7V motherboard and have learnt the following with respect to your question:

1. The CPU bus runs on the A7V runs at 100Mhz which means that you wont notice a great deal in performance gain from the 133Mhz SDRAM as the CPU bus becomes the bottleneck.
2. It is recommended that only CL2 SDRAM is used on the A7V (I think I spotted this in the A7V User Manual). So you can use both 133Mhz and 100Mhz SDRAM in your system so long as both memory types are CL2.
3. If you have 133Mhz SDRAM at CL3 then you can drop the DRAM speed in the BIOS from 133 to 100 which "fools" the system into thinking you have 100Mhz CL2 memory. You will notice the timings change accordingly if you leave SPD (SDRAM Presence Detect)enabled in the BIOS and change the DRAM speed. In other words, assuming you are using 133Mhz SDRAM CL3 the following would occur:

If DRAM Speed in BIOS is set to 100 then SPD sets memory timings to value of 2

If DRAM Speed in BIOS is set to 133 then PSD sets memory to timings to valua of 3

I am not sure of the effect of mixing 100/133Mhz with each memory type having different CLs. The best solution is to buy 100Mhz CL2 or 133Mhz CL2 memory to ensure system stability.

Hope that answers some of your questions
-gogogo5