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So I recently built a PC. After some troubleshooting I find that the BIOS has set the RAM voltage to 1.5V but the OCR RAM requires 1.65V. So I go into the BIOS and increase the voltage. I can get 1.64V and 1.66V. However, 1.64V is drawn green and 1.66V is drawn in magenta. What does this mean? Why the change of colour?

Of course, I've tried to find some manuals for the BIOS (an AWARD) but I've not found anything more detailed than "This screen lets you change the voltages" and nothing about what it all means.

So, should I use 1.64V or 1.66V for my OCR 1.65V rated RAM1. And where can I get more detailed user guides for the BIOS software?

  1. It interesting to note the RAM is advertised as low voltage, yet it requires a higher voltage than the default BIOS setting.
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3 Answers

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I would go for the lower option, and then use the computer to see how you get on. It's important to run some benchmarking tests to test stability on the lower voltage. If it's working fine, try upping the voltage to 1.66v and do the same tests. If your happy with how the PC works with the higher voltage then keep it. Likewise on the lower voltage.

If it was me, I'd air on the side of caution and run it at the lower voltage. Even though it's just 0.01v in the difference between the rated voltage on the RAM to the higher value in the BIOS, it's still an increase of voltage that the RAM isn't specified to do.

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In the end, I set it to 1.64V. I used the SiSoftware Sandra Burn-In (after disabling a few tests that didn't apply and removing my USB RAM stick!), leaving it running overnight. It's cycled through the tests 40 times (CPU, RAM, Disks, Video) so I'm happier about the system now. I'll leave it at 1.64V for now. I just wish there were better manuals for BIOS out there - why is it turning purple? –  Skizz Dec 16 '10 at 14:11
I think on the BIOS it turns purple to indicate "Hold on, if you do this you run the risk of blowing up your RAM". I mean I doubt you'd find any noticeable speed or response difference between the two voltages, so it's probably best to stick it at the 1.64v :) –  mickburkejnr Dec 16 '10 at 14:14
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Can't help you on the colours, but in general:

  • Higher voltage = more heat.
  • Lower voltage = less stability.

But 0.01 V is unlikely to make much difference either way. I'd go with 1.66 V and see what happens.

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In general, your RAM voltages are tolerant of adjustments - in fact, they may well have a significant amount of headroom for overclocking. So a 0.1v increase will likely be a fraction of what the RAM can take.

However, reading between the lines, I'm guessing that you have an i7 processor (?) with some decent-spec RAM (DDR3 1600MHz?), and perhaps even an ASUS motherboard... [How close was I?]

You may have noticed in your motherboard manual or with the blurb that came with your CPU that it stresses that that RAM in Socket 1366 mobos should not go above 1.65v. It's unusual for them to be so explicit, so it suggest there is a real risk, beyond the usual theoretical risk associated with deviating from the spec. I'm not sure if the same potential risk is present with Socket 1156 motherboards.

I suspect that in this case, even a 0.1v increase will ever be an issue, but I'd err on the side of caution. The risks of using the increased voltage will be absolutely minute, but equally, the benefits are non-existent - unless you are intent on heavily over-clocking your RAM.

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Actually, it's an i5 with socket 1156 gigabyte mobo with 1333 RAM. I had an upper limit on the budget. –  Skizz Dec 15 '10 at 13:47
OK, I've not used that combo of components; I think the RAM voltage problem lies only with X58 motherboards (on Socket 1366) which yours clearly isn't, so you should be OK. It doesn't really matter anyway; I strongly suspect it doesn't make a blind bit of difference which voltage you choose either way! –  CJM Dec 15 '10 at 15:14
You're right about the voltage paranoia, but I'd point out that random flucuations in power are likely to be more than +/- 0.1v at some point in the lifetime of the machine, so I wouldn't sweat that tiny bit. I wouldn't intentionally highball it though! –  Shinrai Dec 15 '10 at 15:22
@Shinrai - the problem lies with warranties - 'Did you run you RAM more than 1 attoVolt over the designated 1.65v?'. 'Yes'. 'Sorry, you can't have a replacement!'. In reality, the RAM is probably slightly under-volted by the mobo, so you wouldn't be breaching the threshold anyway! ;) –  CJM Dec 16 '10 at 12:53
that too. ;) –  Shinrai Dec 17 '10 at 16:49
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