Memory voltage

[cbf]

I have a gigabyte GA-EX38-DQ6 MB. The manual says its DIMM sockets are 1.8v. The memory I want to install is DDR2 1200 at 2.35V.

Will I have problems? Even 1066 memory runs at 2.1v

 

[FlorinR]

The standard voltage for DDR2 is 1.8 V. For about every DIMM are voltages specified by the manufacturer with you can "play" and obtain some tight latency or high freq. So don't worry !

 

[bilbat]

Yes, you WILL have problems, and yes, you CAN make it work.

There's a GREAT Gigabyte forum over at: http://forums.tweaktown.com/f69 You'll find a pair of step-by-step 'stickies', one on RAM testing/tweaking, and one on GB overclocking.

Gb boards, in general, 'like' Mushkin RAM. Not to say others' WON"T work, just that Mushkins seem to take less fiddling with, and if you ARE willing to fiddle, might OC better. I'm planning a new workstation, and was going to buy 8Gb OCZ 1066 as it was a little cheaper, & they seem to have good support (especially at NewEgg) but, it seemed to me, I'd GLADLY pay $15 a stick to cut several hours of cursing at the BIOS while tweaking.

Do you already have the RAM? If not, I'd suggest just going with some Mushkin 996599 1066, and saving yourself 'X' amount of grief. All DDR2 is essentially 800; the fast ones are 'speed binned': selected for performance. They have an on-stick stored timing profile (SPD) which tells the system how to time them, and fast ones usually have an EPP (Enhanced Performance Profile) that will tell the MOBO how to 'kick them up', but what they don't like to publicize is that it seldom works, without additional BIOS tuning.

High speed RAM is not all that the raw frequency promises. Let's look at some, with a little bit of analysis thrown in:

[prices are today @ NewEgg]

2Gb (1x2) OCZ 'Reaper'

Bus Price Latency {Avg Latency, i.e., (4+4+4+15)/4, or 6.75}
800 42.99 4-4-4-15 {6.75} $42.99
1066 45.99 5-5-5-15 {7.50} $45.99
1200 82.99 5-5-5-18 {8.25} $82.99

now, at 800, your rising edge to rising edge RAM Bus cycle is 1000/800, or 1.25 NanoSeconds(nS)
at 1066, .938 nS
at 1200, .833 nS;

so, {AvgLatency} x BusCycle = rough estimate of access/throughput time, or
800 6.75x1.25=8.44nS
1066 7.50x.938=7.04nS or ~7% faster than 800
1200 8.25x.833=6.87nS or ~18% faster than 800

even though the raw 1066 bus is 33% faster than 800, and 1200 is 50% faster - and that's WITHOUT the likely additional slowdowns from MCH strap latencies at higher speeds, higher tRD's, and non-optimal, high denominator FSB/MCH ratios (see: http://www.anandtech.com/mb/showdoc.aspx?i=3208&p=4 )

That means for the 7% increase in price for 1033, you might hope to see a close to 5-7% increase in actual performance, but for the 93% higher price of 1200, you'll be lucky to get 15% in real application...

Add in the fact that, if all the letters (tRCD, tWR, tRD phase, etc.) and numbers (CPU Vcore vs. Vterm, MCH skew, etc.) on the BIOS screen don't yet mean anything to you, you will be trying to shoot without aiming - tune memory without a real understanding of what's going on, and why; or posting time after time to have someone help you with parameters, and waiting between posts and answers. It's sort of like the old conundrum about an infinite number monkeys typing on an infinite number of typewriters - how long 'till they produce 'Hamlet'? How long 'till they pound the typewriters into oblivion out of sheer frustration?

Go over to tweaktown and search "1300" - see the saga of someone who payed a fortune for ultra-fast ram, the sheer number of posts, and note the ones where he threatens to sell them to the lowest bidder just to be rid of the on-going headache!

I plan to buy six sticks of 1066, and 'push' them one at a time, to find the fastest four. Then, I intend to actually underclock them at around 940 to get 1:1, attempt to 'squeeze' a CAS of 4 and a tRD of six out of 'em, and am fully expecting to have troubles to work out, getting four sticks at once optimized... I'll set aside a couple of weeks of spare time for the project, and will be honestly surprised if that covers it - but, then, I've got eighty or a hundred hours just into case/MOBO preparation already!

 

[cbf]

Thanks for very full answer