The REAL speed of the Samsung 950 Pro M.2

m.2 Sam950pro

The newer ultra-fast M.2 drives such as the Samsung 950 Pro promise to give  absolutely amazing performance (up to 2.5GB/s read and 1.5GB/s write!), but one major issue with these drives is that they will throttle if the drive gets too hot.
When the Samsung 950 Pro gets too hot, the speed of the drive is greatly reduced – in a worst case situation it may even end up slower than a standard SSD.
If you are purchasing a M.2 drive because you need high transfer speeds, you won’t like to hear how much and how quickly it will slow down if it gets too hot.
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A lot of our test results really surprised us.
We knew that M.2 drives would throttle if they got too hot, but we didn’t know that we could cause it to happen so quickly or quite to the extent we measured.
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The ambient temperature within the system has a massive effect on when the drive throttles.
It makes sense that a drive will throttle sooner in a hotter environment, but in the worst case we were seeing throttling in as soon as six or seven seconds!
The more exposed the M.2 drive, the longer it takes to throttle, especially when the system was put under a load.
Single GPU Dual GPU
Bottom M.2 Slot Throttled by ~52% after ~40 sec Throttled by ~68% after ~14-17 sec
Top M.2 Slot Throttled by ~50% after ~25 sec Throttled by ~76% after ~7 sec
The promise of greater speeds is greatly undermined after a few short seconds by throttling due to heat, as much as 76% in as little as 7 seconds!!!
The REAL speed of the Samsung 950 Pro M.2