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A comment on Video RAM Transplant Doubles RTX3070 Memory to 16GB. Parent comment

Re:Video RAM Transplant Doubles RTX3070 Memory to 16GB by osamagirl69 on Wednesday March 24, 2021 @12:26PM (#26569344)
The reason why the VRM is tightly integrated with the asic is that there are extremely stringent constraints on the power integrity connecting these two parts. To first order, a decent GPU draws about 1000 amps of current, so even a single milliohm of resistance would absorb the entire voltage supply. Not just the ripple tolerance, the entire power rail! This is before we even get into the ludicrous requirements on transient behavior, inductance, etc, of the connection.

They do make GPUs with a socket for the asic (typically only used in test labs) so it is theoretically possible that you could for example... buy a 2070 carrier and then get nvidia to sell you a 2080 asic to socket into the carrier. But generally the technologies used in GPUs change every generation (memory technology, number of memory channels, display technologies, etc) so you probabably wouldn't be able to keep your carrier more than 1 maybe 2 generations tops.

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Re:Video RAM Transplant Doubles RTX3070 Memory to 16GB by SomeHacker44 on Wednesday March 24, 2021 @12:29PM (#26569384)
I think there is a typo in "1000 amps of current."
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Re:Video RAM Transplant Doubles RTX3070 Memory to 16GB by osamagirl69 on Wednesday March 24, 2021 @12:43PM (#26569602)
No, a modern GPU literally draws about 1000 amps of current. For example, a non-overclocked 3090 draws about 500w under load (some of this goes to memory, but that is powered by the motherboard not by the external power connector), at a Vcore of roughly 1.1v which gives a bit over 450 amps--on average! The peak power consumption (as measured on a nanosecond scale being consumed by the asic itself) can easily be double the average power consumption due to the bursty nature of asic power draw.
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Re:Video RAM Transplant Doubles RTX3070 Memory to 16GB by winrid on Wednesday March 24, 2021 @03:17PM (#26571737)
Remember that it's not just one core - that's what makes a GPU so powerful. My understanding is it's hundreds or thousands of 1.1v cores, which adds up to the 500w.

EDIT - wait, what GPU draws 500w? I can't find one.

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Re:Video RAM Transplant Doubles RTX3070 Memory to 16GB by vizzier on Wednesday March 24, 2021 @07:54PM (#26574673)
Not sure any base cards draw this much. But might be doable via modding:

https://www.notebookcheck.net/The-NVIDIA-GeForce-RTX-3090-ma...

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Re:Video RAM Transplant Doubles RTX3070 Memory to 16GB by xxs on Wednesday March 24, 2021 @12:34PM (#26569468)
for desktop GPUs 1000 is bit much, but 600-700A are totally doable under LN2
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Re:Video RAM Transplant Doubles RTX3070 Memory to 16GB by dogsgobork on Wednesday March 24, 2021 @12:54PM (#26569811)
I think people are conflating watts and amps, watts measure power, amps measure flow. Watts = amps * volts. High power usage with low voltages results in high amperage.
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Re:Video RAM Transplant Doubles RTX3070 Memory to 16GB by xxs on Wednesday March 24, 2021 @12:55PM (#26569830)
Even so, in this very case the amps are higher than the watts(!) as the voltage is below 1V.
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Re:Video RAM Transplant Doubles RTX3070 Memory to 16GB by zokier on Wednesday March 24, 2021 @03:55PM (#26572131)
If Vcore is near 1 volt, then the magnitude difference between amps and watts is pretty small for the sort of discussion we are h aving
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