How does one tell if SDRAM is high or low density? I read somewhere that if the RAM uses modeules that are greater than 64 MB each, that would indicate that the stick is high density. Is tis true? If not, please tell me how to tell the difference.
There are many different densities, high and low are relative to the chipset you're using. What seems to be the problem?
For Intel BX/ZX/LX/EX/TX chipsets, the density limit is 16MB per CHIP. That means it supports a maximum of 256MB on a 16-chip module, 128MB max on an 8-chip module, etc. And it also supports lower densities.
For the Intel VX chipset it was really bad, 2MB per chip.
Most other chipsets have much higher density limits, so that you'll likely not need to ask the density question. But since you're asking, you'd better have a reason why!
In the days of the VX, anything greater than 2MB/chip was considered high-density. In the days of the BX, anything greater than 16MB/chip was considered high density, etc.
Wow, that might be a problem! Compaq, HP, and IBM have had some strange limitations due to their custom BIOS implementation. I'd suggest you use Crucial's memory selector (at their site) to find compatible RAM.
If you're able to find cheap old RAM, the stuff I recommended for the BX should work fine (16-chips for 256MB, ie 8 chips on each side).