Overclock.net banner

1 - 4 of 4 Posts

·
Registered
Joined
·
1,107 Posts
Discussion Starter · #1 ·
I'm kinda confused about this topic...

What really is the problem with running high voltage on the ram?

According to Intel Haswell datasheet, the maximum DDR3 voltage for the processor is 1.5V +0.05% = 1.575V. This seems very conservative since a lot of people out there are running XMP memory at 1.65V. I think we can consider 1.65V "safe". But what about pushing higher than 1.65V?

Apparently, the problem isn't the RAM itself, but the IMC. I read that the RAM voltage and the IMC (System agent, VCCIOA and VCCIOD on Haswell?) voltage should be kept within at least 0.6V range to avoid instability.

So in the end, if I can keep a reasonable offset on these imc related voltage (Sin's guide on Haswell OC recommends max 0.2 offset) I won't damage my cpu? Or does the voltage of the ram goes though the cpu or what? I thought the ram had its own vrm etc.

Thanks
 

·
Registered
Joined
·
1,096 Posts
There is no problem as long as it is done accordingly. Ie. for overclocking, the RAM/IMC needs more Voltage, etc. But if someone's trying to get DDR3-1866 to work and they punch in VDIMM 1.80V, IMC 1.40V for the sake of just wondering if it will get the darn system stable, then they're in for a surprise.

The standard is 1.50V, the enthusiast (XMP) limit is 1.65V for DDR3, and anything above is 'extreme'. Extreme users generally know what they are doing, many people run 1.70V+ daily if their RAM is effective with it, so it depends. Same with IMC Voltage, many have to push 1.20V+ for DDR3-2400+, even with the DRAM Voltage at 1.65V, so high voltages is nothing new for enthusiast/extreme users. The key is making sure the additional voltage is necessary and being used. Excess voltage and the need to regulate is what can cause hardware damage.

cheers happy oc & holidays
 

·
Registered
Joined
·
762 Posts
as far as i know, that voltage guide harks back to the x58 days, and exists because high ram required a high uncore. i think the uncore had to be within 0.5v of the uncore, or the uncore would be damaged. seeing as how this was done with baseclock rather than memory straps nowadays, i dont think its as relevant as it once was.

i bench a lot, and have never had any issues. my pc is only on for benching, so its 24/7 clocks are 2400mhz 8-12-8, 1.9v on the ram and +0.2v on the system agent etc. ram does not degrade, nor is it killed by voltages unless you're talking ln2 at which point you're looking at 2.2v ir you're lucky.

bear in mind that JEDEC (the organisation that sets up the industry standards for RAM) states that memory modules must withstand up to 1.975 volts before incurring permanent damage.
 
1 - 4 of 4 Posts
Top