Some build questions regarding power and PCI-e bandwidth


Hi there friends,


My name is Alex, and I am a software engineer working in military avionics. This is just to say I am well versed with computers, and no stranger to tech. The last computer I bought (and still is my daily driver) is a MacBook Air 11".....from 2013. It's been time for an upgrade for quite a while now. For pretty much as long as I can remember I have wanted to build my own computer, and now that is finally an option for me! I've spec'd out all the parts and there are some general questions I have. I know this build might be in the category of over kill, but I have waited TOO LONG for a mid-tier computer. I have built a few computers for work but never for myself, and with the new CPU/GPU from AMD it is finally time.  I hope you guys can help me!!!


Parts List:

CPU: Ryzen 9 5950x (I plan on buying this at a MicroCenter location on the drop date. I know there will be a line, but my question is how long? Should I arrive the day before with a tent?! Or will showing up 1-2 hours before the opening time be adequate? @ Tustin location)

GPU: Ryzen Rx 6950 xt

Motherboard: Mini-ITX, x570 chipset, 1x PCI-e Gen 4x16. (LINK)

RAM: 16GBx2 @ 3200Hz

Storage: M.2 PCI-e Gen4x4, 1Tb

Case: NZXT H1 (Ships with PCI-e Gen3 Riser Card, so I will need to upgrade to Gen4 if I want full capability. BUT SHOULD I EVEN DO THIS? As Jay puts so wonderfully here, would it even matter if I don't use full Gen4 capability?  I also have a question down below regarding the bandwidth.)



So, as you might notice there is no AIO cooler and no PSU in the above list. That is because the NZXT H1 chassis has them both built in (140mm AIO and a 650W SFX-L PSU respectively). This is where my first big question and issue arises. I am determined to make this THE sff build. Yes I know I'm trying to cram a lot of power in tight area. Yes, I know I will almost certainly be battling heat and thermal throttling. I this is a "me problem" and I have some custom solutions I want to try. If anyone is interested when the build is done I may share here again. But back to my original point...the case comes with a 650W psu. I like this because its already integrated in so less work for me, but more importantly I don't have to buy one by its self.


Question #1!

Or do I?? According to AMD, the Ryzen 9 5000 series has a TPC of 105W. No problem. AMD's Radeon 6900 series claims to have a power draw of 300W. Also no problem. Making for an estimated total of ~400W. Lets just say the motherboard(~30W), fans/pump(~100W), ram(~5W), storage(~10W)....(am I missing anything else) take up total ~150W (over estimate). This would bring our total power consumption to ~550W. And therefore the integrated 650W PSU in the case will work wonderfully. What is making me question is the fact that on the AMD site, on the 6900 GPU series page, they state "Minimum PSU Recommendation: 850 W". WOW. That is crazy, my general belief is that 850W is going to be WAY OVERKILL for any build. So what’s up? Should I get a larger PSU? If so, I will probably change my case and go a different route.



Question #2!

So it’s pretty clear that the new Gen4 PCI-e is a beast. Meaning, the new GPU will not use all, what 200Gb/s? that is available. So my question is will splitting the PCI-e port effect the overall performance? If I wanted to split the port to support a network card and the GPU will it work? If the network card takes only one PCI-e lane, then will the GPU only have access to 15 lanes? will this matter, or since the bandwidth is so high I won't even see a difference? If I don't upgrade to a Gen 4 riser cable and still use the Gen 3 cable included, will that work? I guess there is a lot of unknowns here since this hardware is not even released yet.



But that’s it! Any information or advice about anything would be much appreciated! Thank you for your time and consideration!


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