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Q. Do RAM voltages make a difference?

In your recent article 'Specifying and Building A Dual-core Desktop PC' (printed in SOS February 2007), the RAM chosen was Corsair Twin 2X2048 6400, which is specified for 1.9V. The selected Intel motherboard specifies 1.8V only. Why did this not result in failure to boot up?

Kim Launer

PC music specialist Martin Walker replies: Well spotted Kim! As I said in my feature, "some motherboards seem fussy about what RAM they use, and one recurring problem with some models, including Gigabyte's GA965P DS4 and my choice, Intel's DP965LT, is that they supply only 1.8V to the RAM by default. Some RAM prefers a minimum of 1.9V and you won't even be able to get into the BIOS to determine what's wrong in such cases."

I was keen to highlight such issues because, as someone once said, a little knowledge can be a dangerous thing, and many DIY PC builders have found to their cost that their set of PC parts simply won't boot up at all. Fortunately, you will still know what the problem is, even without any on-screen feedback, since the integral motherboard 'speaker' (nowadays in reality a tiny buzzer) will produce three long beeps that indicate a 'memory error'.

The reason the RAM/motherboard combination worked in the article, is alluded to by the words "by default". As part of my research for my chosen motherboard, I read all the geeky stuff I could find on Internet forums, and in particular the 'Official Intel DP965LT Thread' on the Anandtech hardware analysis forums which, as I write, already runs to 19 pages (forums.anandtech.com/messageview.aspx?catid=29&threadid=1908407). From this I learned (among many other things) that several system builders were talking directly to Intel tech support about various early issues, and that by July 2006, Intel had released a new BIOS update that was claimed to use the RAM's SPD (Serial Presence Detect) feature to auto-select 1.8V or 1.9V. This was confirmed by other builders, who could now boot with 1.9V RAM for the first time after flashing this BIOS, and the same Corsair RAM/motherboard combination has since been employed successfully by many PC builders.

If you've encountered this problem and need the BIOS update, it can be found on-line at downloadfinder.intel.com: type 'DP965LT' into the search field. 

Published April 2007