Ram makes PC ultra slow? Older 775 systems.

Trying to put together some old systems for PC less friends, and have come across a strange issue.

The first is an old DG965SS board, 775 socket and 965 chipset.

I had 2x 2gb ddr2 800 sticks which I fitted, it loaded up and seemed to work, but was unusably slow, the windows 7 install (from usb stick to ssd) to 2 hours or so. When it was finally loaded it would take an age to load up, once loaded with task manager open, just moving the mouse took the CPU usage up to 80-90%.

Swapped out the ram to 2x 1gb sticks, and 2x 512mb 667 sticks, and it was fine. Assumed the ram was faulty.

Built another 775 system today, on a GA-EG43M-S2H board, bought 4x 1gb ddr2 667 to go with it, and seem to be getting the same issue again. Tried the "faulty" ram from the previous build and have the same issue. Typically the pc with the working ram has gone now so I can't swap it out.

Both Core 2 duo e7500 processors if that makes any difference.

Surely 6 faulty sticks of ram, with the same fault is very unlikely. The same fault on 2 board with 2 different sets of ram, with 2 different processors is strange, leads me to think it could be a bios setting. Anyone got any ideas on this?

Cheers

Your symptoms look more like thermal throttling... At least, I would suspect the heatsink mounting when you can high CPU usage reports from the OS...

Check the motherboard for bowing!

Could be a compatibility issue with the chipset. Those socket 775 era boards could be very picky about RAM.