As a hobbyist high performance programmer, I've been waiting for Intel's AVX512 instruction set for years. And it's finally here!
And really, this is the only point of this build. But I figured that if I'm going to do a build, I might as well try out a few other things that I've been wanting to do a while:
Parts and Pricing:
This build was somewhat time-sensitive since I've been waiting for almost 4 years for this. But more importantly, I maintain a semi-popular benchmark/stress-tester. And I've had numerous requests for AVX512 support for the past month prior to and in the days following the Skylake X release.
Processor: Core i9 7900X
As much as I wanted to get the cheaper 8-core Core i7 7820X instead, I actually had no choice. There are numerous sources that say that only the Core i9s will have the "full-throughput" AVX512. The lower-end 6-core and 8-core parts only have half speed AVX512. And the Kaby Lake X parts don't have any AVX512 at all.
Other than that, this thing is REALLY FAST! I'm not gonna rule out a future upgrade by trading it up for the Core i9 7980XE. The time I save waiting for my code to compile is totally worth it. The extra PCIe lanes will be useful later if and when I migrate my hard drive towers to it (with 2 PCIe x8 SAS controllers).
Threadripper is a no-go because it lacks AVX512. And I wouldn't be able to reuse this motherboard.
Motherboard: Gigabyte X299 AORUS Gaming 7
What's not to love about this board? Other than being a bit on the expensive side... (There is one major problem that came up during stress-testing which I'll explain later.)
Video Card: Gigabyte - GeForce GTX 1050
This was actually the hardest part to spec out. It is the only card that satisfied my list of requirements:
The video card purchase came after I had ordered and setup the case and 360 radiator. So I was able to physically measure the space I had before selecting a video card.
Because the margins were so thin, I had to get very precise measurements. So I used the video card from my Ryzen build to figure out exactly how the dimensions that were listed online were being measured in relation to that card that I already had. Then I could extrapolate that to other video cards I was looking at.
It turns out that length measurements listed on Newegg do not include the part of the PCI slot that sticks out. (PCI mounts to the case are shaped like an L with the top part sticking out the back.)
The 9 in. restriction effectively ruled out all RGB ASUS cards as well as all higher-end Gigabyte cards for both Nvidia and Radeon. Not even the Gigabyte RGB 1050 Ti would fit. Looking to other manufacturers didn't give any other options either.
Case: Corsair 460X RGB
It has tempered glass, RGB fans, and is pretty cool to look at. More importantly, it fits into a suitcase that's suitable for airport check-in. And there's enough space to pad down the sides to protect the tempered glass.
Power Supply: Thermaltake - Toughpower Grand RGB 850W
It has RGB. And it's small enough to fit in the case without removing the drive bays. 850W is sufficient since I'm not running any fancy video cards.
Memory: G.SKILL TridentZ 128GB 8 x 16GB DDR4 3300 MHz (Black/White)
This one hurts the most - because it's the only thing that could be RGB but isn't.
The reason why these aren't RGB is because I picked it up back in March while it was on sale on Newegg for $800. While I didn't have a particular need for it at the time, I was anticipating a Skylake X build later in the year. And given all the news about the DDR4 shortage, I knew I had to grab it. And I'm glad I did as it sold out within an hour after I ordered it. It's now listed at $1400. And no I'm not gonna spend $1.4k for the RGB version.
For the 4 months I've had this ram before this build, I ran it in my older 5960X build. But since that was a 1st generation DDR4 system, it couldn't handle high speed memory and wasn't stable above the stock 2133 MHz. But this Skylake X build has no problems running it at 3200 MHz. I may try clocking it higher later.
Storage: Samsung 500GB + Toshiba 7200 RPM Hard Drive
The SSD was pulled from my Core i7 5960X build. The hard drive was one of many I had sitting around.
This entire build (including the monitor, keyboard/mouse, and speakers) became my secondary work-desk. My primary work-desk remains my Ryzen build.
The overclocking that I did for this build is not the usual overclock. Rather than trying to push the absolute frequency as high as possible, I tried to get the AVX and AVX512 stable at as high as frequency as possible.
At stock settings, the 7900X specifies:
If you read around online, you'll find that:
Once you exceed thermal limits, the processor will throttle in multiple ways. This may be a drop in clock speed. But more commonly, the clock speed stays the same and the performance plunges for some reason. You can read more about that here: http://www.overclock.net/t/1634045/skylake-x-phantom-throttling
In my current overclock, I run all cores at 4.5 GHz non-AVX, 4.0 GHz AVX, and 3.8 GHz AVX512.
Because I didn't touch the top frequency, I never had to raise the voltage. And I never crashed the system. Instead, the game I played was figuring out which thermal limits to increase to allow me to run AVX and AVX512 at higher frequencies without throttling.
Even though I didn't delid the processor (nor do I intend to), I was rarely able to overheat it by running AVX and AVX512 code. Even when I disable all thermal limits, the motherboard/BIOS still throttles the processor before I'm ever able to hit temperature limits.
This makes it impossible to do extreme overclocks and is my main gripe about this motherboard. Silicon Lottery has also noticed this and he says it makes these Gigabyte boards unusable for his purposes.
So while this Gigabyte board is aesthetically pleasing and boasts the hardware to support extreme overclocks, the software/BIOS currently does not allow it. Therefore, form over function.
(Edit: As of August, this throttling problem has been solved. See the link above.)
Likewise, there are currently no high-powered RGB fans. So if I want extra cooling, I'd need to sacrifice the eye candy. Again, form over function.
Possible Future Upgrades: