Personal computing discussed
Moderators: renee, Flying Fox, Thresher
Kougar wrote:It is reassuring to know the VRMs can self-throttle from high temps on their own, but I think it's also disturbing that chunks of finless metal are supposed to somehow dissipate the heat from 300-400w VRM loads.
Waco wrote:They're 90%+ efficient, so we're only talking about 30-40 watts of heat to dissipate (assuming all that 100% of the power goes straight to the CPU and no other components in the system...) and they'll happily run at 100C for years without issue.
Kougar wrote:Waco wrote:They're 90%+ efficient, so we're only talking about 30-40 watts of heat to dissipate (assuming all that 100% of the power goes straight to the CPU and no other components in the system...) and they'll happily run at 100C for years without issue.
Are they really, though? ASUS was playing coy and wouldn't tell Tom what the VRM was specc'd to handle nor its safe thermal limit. All they would say was 400w was well within the design spec, but the 105c temps he was getting was in fact a problem.
blahsaysblah wrote:An 8-pin EPS connector has 4 hot pins, vs a GPU 8-pins 3 hot.
synthtel2 wrote:What I most wonder about this whole debacle is who decided that many-core chips like these need to run all-core clocks this high. If you've got a lightly threaded workload that isn't running as fast as you want, you don't have many choices other than turning up the clocks. SKL-X turbo seems good enough that that's no excuse for stupid high all-core clocks. If you've got a workload that can actually use 10 cores, and it isn't running fast enough, it would probably be much better served by going to 12C (~1.2x power cost) than by boosting clocks 20% (>1.4x power cost). Obviously Intel wants to keep their profit margins by not selling anyone more silicon than they have to, but optimizing for perf/mm2 at the expense of perf/W isn't how you end up commanding the kind of prices Intel likes to command.
Vhalidictes wrote:
I'm going to go out on a limb and guess that you've never had a one/two core application jump to a "slow"/base-clocked core. On Windows 10 it happens quite frequently. This is particularly fun when it's combined with core parking/power-saving modes.
Kougar wrote:blahsaysblah wrote:An 8-pin EPS connector has 4 hot pins, vs a GPU 8-pins 3 hot.
High-end GPUs that draw this kind of power have 6 hot pins, so you're missing half of them. It also means GPUs have more hot pins than the EPS12V connector, and let us not forget that the GPU draws up to 75w directly from the PCIe slot in addition to those six PCIe power pins.
Again, I have a serious problem with this much current being drawn from just 4 hot EPS12V pins, especially as my understanding is the EPS12V connectors also happens to power the quad-channel memory banks. Maybe I'm wrong on that detail, it's been awhile since I've seen really in depth mainboard reviews that touched on this.
Something I mentioned on the TR news article is that the 7920X is a 12-core HCC chip. Almost half of the die area is dark silicon, so combined with a much larger die area and probably real solder the HCC chips should have more headroom before thermal throttling kicks in, which means more power draw than even what the 7900X can do.
Captain Ned wrote:The wiring between the PSU and either the EPS12V or the 6/8 pin GPU plugs is 18-gauge. The US National Electric Code limits ampacity in 18-gauge cords to 7 amps per if 3 or more conductors, or 10 amps if but 2.
To stay in spec, a 4-hot/8-pin EPS12V can legally carry 28 amps at 12 volts, or 300 watts per EPS12V. A 6-hot/8-pin GPU can carry 42 amps, or 504 watts per 8-pin GPU. The cords from the PSU are NOT the problem. They're well within spec.
The only source of 3.3v and 5V to a modern motherboard comes from the ATX 24-pin (absent older mobos with a Molex plug up against a slot).
If the mobo mfgs are skimping on the sockets, then it's all on them. The PSU is NOT the problem.
blahsaysblah wrote:That chart didnt even say what type of wire, material, stranded and was showing numbers for STOW sheating of all things.
Captain Ned wrote:To stay in spec, a 4-hot/8-pin EPS12V can legally carry 28 amps at 12 volts, or 300 watts per EPS12V.
Kougar wrote:Captain Ned wrote:To stay in spec, a 4-hot/8-pin EPS12V can legally carry 28 amps at 12 volts, or 300 watts per EPS12V.
Der8auer has posted a new, short vid on the redesigned ASUS Apex VRM cooling. He was able to attain 340 watts without the VRMs throttling making it the first board to do so. The cooler actually has fins, they added a backplate, and even a VRM fan. https://youtu.be/hejMP5hrhjc
I still say if a 7900X can do 340 on CLC cooling then the 7920x with almost 45% of the chip area being dark silicon +2 extra cores should do one better. I'm looking forward to JonnyGuru testing EPS12V cable temps when he gets back from his vacation. Even in an 8+4 configuration Threadripper is going to be interesting as well.
just brew it! wrote:Would've vastly preferred if they could've gotten decent cooling for the VRMs without the use of an additional fan. It's just one more thing to fail.
just brew it! wrote:Would've vastly preferred if they could've gotten decent cooling for the VRMs without the use of an additional fan. It's just one more thing to fail.
4.2.2.4 +12V Power Connector
Connector: Molex* 0039012040 or equivalent.
Contact: Molex 44476 - 1112 (HCS) or equivalent (Mating motherboard connector is Molex 39-29-9042 or equivalent).
NOTES:
1. 18 AWG wire.
blahsaysblah wrote:If you lookup the Molex 44476-1112 (HCS, high current series), it lists 11 amps.
Captain Ned wrote:I should make you lot work in my dirt-floor breaker panel where I live. Talk about a Sorting Hat. Have fun with the 240V/30A double breaker circuit.
I know I've said it many times before, but I have not the slightest qualm about working in there live. Mainly because my headlamp buggered off and the cobwebs are of mystical proportions.