Intel Q8200 Core2Quad and memtest86

If you've been following my other thread, you know that I'm dealing with
a gigabyte motherboard (EP45-DS3L) that as of yet I can't get any 4gb
ddr2 kit to work.

Specs for the EP45-DS3L:

- Support for DDR2 1333+/1066/800/667 MHz memory modules
- 4 x 1.8V DDR2 DIMM sockets supporting up to 16 GB of system memory
(I think this is wrong - I think it only supports 2gb dimms)
- Dual channel memory architecture
- North Bridge: Intel P45 Express Chipset
- South Bridge: Intel ICH10

I can get single and pairs of 1gb dimms to work, and single 2gb dimms,
but not a pair of 2gb dimms.

When I've got a working configuration (as per above) I can run the
single-core version of memtest86 (v 3.5) booted from a floppy and it
runs for as long as I let it. Several complete passes at least.

But when I boot the multi-core version of memtest86, it freezes
immediately after it starts.

Are there any known issues with the Q8200 (or core2 quads in general)
and memtest86?

Or perhaps the issue with with memtest86 and the P45 / ICH10 chipset?