On 11/12/10 12:21 PM, Keith Roberts wrote: 
On Fri, 12 Nov 2010, John R Pierce wrote:
that sounds quite likely. some of those modules have two banks on the
single module, and I seriously doubt a system is going to like a single
bank and a dual bank module in a dual channel environment.

I got in the habit a long time ago of *always* using 
matched memory modules.

I've learnt my lesson now John.

Well at least I won't mix hi and lo density modules again.

Here's the link for my Asrock m/b:

http://www.crucial.com/uk/store/listparts.aspx?model=K7S8XE%20R3.0

It does not support dual channel memory.

no, but look at these constraints on the memory vs cpu FSB speeds
http://www.asrock.com/mb/overview.asp?Model=K7S8XE

CPU - Socket 462, supporting AMD Athlon, Athlon XP, Duron
- FSB 400/333/266/200 MHz
Chipset - SiS® 748
Memory - DDR non-ECC, un-buffered memory
- DDR400, Max. capacity of system memory: 1GB (FSB 400/333 MHz)*
- DDR333, Max. capacity of system memory: 2GB (FSB 400/333/266/200 MHz)
- DDR266/200, Max. capacity of system memory: 3GB (FSB 333/266/200 MHz)

*According to SiS® official document, SiS® 748 chipset has limitation DDR supports:
CPU at FSB 200MHz mode, it will NOT support DDR400
CPU at FSB 333MHz mode, it will NOT support DDR200
CPU at FSB 400MHz mode, it will NOT support DDR200/DDR266


I don't know which CPU you have, but, for instance, if its a 400Mhz CPU, you can't use 200/266 memory, and if you're not using 200/266 memory, you can't have 3 dimms at all.   Your PC2100 is 266Mhz memory.

And let just toss out that I personally would scrap any motherboard containing SiS (or VIA) chipsets in a blink if it was giving me any trouble at all.