Hey Everyone hope you are doing well. I was hoping for a bit of advice as I am struggling to decide on the right CPU for my new build.
I am putting together a very small but hopefully powerful PC to be used for running virtual machines with the host operating system Windows 11 and several guest operating systems: Windows 11, Windows Server, Ubuntu. This is a no GPU build, focused on performance - snappiness of the user experience when using VMWare Workstation Pro.
CPU: Ryzen 7950x OR Ryzen 9900x
CPU Cooler: Thermalright AXP90-X53 Black
Case+PSU : InWin Chopin Max, 200w
Motherboard: ASRock A620i
GPU: NA
RAM: Corsair Vengenace 64 GB (32x2) DDR5 6000MHz CL30
Storage: WD_BLACK SN850X 1TB NVMe
Secondary Storage: Older Samsung 970 EVO Plus 2TB
In my price range I am looking at 7950x for the higher core count and 9900x for the higher single core performance. I am quite unable to figure out which one would feel more responsive when interacting with the type 2 hypervisor (core count vs higher single core perf). I believe I would have to run either in ECO mode at 105w or 65w due to the PSU limitation of 200w imposed by the InWin Chopin Max case.
Which one would be the better choice would you say?
To answer that depends on which cpu is more efficient at low power setting. My thought the 9900x would run better with limited power. Based that it is newer and that lower number of cores. So I have 7950 the on board gpu is fine for office use apps ,but not for anything more . Scored 826 in time spy. I will note that from driver version from when CPU was released.
In this Reddit post I see mentioned the 9900X in 105W Eco Mode getting a Cinebench R23 multi-core score of 33,176 at 69°C with an ATMOS 240 cooler. At stock TDP r23 score was 33,003 at 76°C with the same ATMOS 240 cooler.
Further down the OP tested the 9900x at stock W with both AIO - C23 MC - 33,662 (76c TDIE) and AIR (X47FC) C23 MC - 30,350 (95c TDIE) .
There is no mention of testing with the air cooler at 105w, but I would suspect the temperature would be a bit lower and my build using AXP90-X53 instead of x47 could help a bit.
I was unable to find the same CPU cooler tested with 7950x. This youtube video shows the following temps using the Noctua L9a AM4 cooler.
Stock TDP - r23 multicore score: 30512 - 95 C
65w ECO - r23 multicore score: 27289 - 76 C
105w ECO - r23 multicore score: 33752 - 95 C
IMO this question doesn’t make much sense. Running a hypervisor and a guest OS isn’t gonna feel different in either case - they aren’t that resource intensive on their own. It’s what you’ll gonna run inside what matters.
I think that is generally true. The virtual machines consist of a simulation of an enterprise network (Windows 11 Client Workstation, Windows Server DC, pfSense) and some security tools ( Splunk, Velociraptor on Ubuntu, Kali Linux, Windows Analysis machine). These are used interactively by me to simulate activity and then investigate by querying Splunk or analyzing data in the WIndows Analysis machine.
They are not all running at full capacity at the same time. However in the past I have experienced hiccups or freezes using my 4750U laptop or 7700 desktop both with 32 GB ram. (I did see a noticeable improvement moving from 4750U to 7700 but there were still slowdowns here and there).
I am not sure what caused the poor performance and I am looking to upgrade my workstation to address that. And so my question is along the lines of would 16 cores be better suited to avoid this or the better single core performance of the 9000 series?
Then hard to say which is better. Profile and troubleshoot that, and you’ll find the answer. Could be a lack of memory, 32GB isn’t that much for a couple of windows VMs
Thank you, I went with 64 GB this time to address that. In terms of CPU I was considering slightly over allocating Cores (if choosing 9900x) when there is no constant high CPU usage on the host.
Here is my base resource config moving forward. Would over allocate in some cases if appropriate. What do you think?
In either case (12 cores or 16 cores) this is overprovisioning. You’re saying not all are used all the time, but that still quite vague. The hiccups and freezes you’ve mentioned - what was that about, how did they manifested?
Can you get both CPUs and try, and then return one?
In either case (12 cores or 16 cores) this is overprovisioning. You’re saying not all are used all the time, but that still quite vague.
Sure, what I mean by “not all used all the time” that is:
When all those VMs are running they do not all run intensive tasks such that the multicore load would be 100%. (applicable to r7 7700 and this build)
I am the only user so there is no overhead from activity from other users.
I was reading about when it is ok to overprovision here. "You can over-provision CPUs across all your VMs, especially the ones that are mostly idle. Do be careful of the number of vCPUs you give any individual VM, as CPU Ready time will inch up when you add more processors and/or have more VMs running. "
The hiccups and freezes you’ve mentioned - what was that about, how did they manifested?
While allocating the resources I was careful not to over allocate RAM. In task manager it did not show as full rather 28 out of 31 or so.
They manifested in the Windows guests. In particular Windows Server VM freezing - my suspicion related to automatic Windows Updates as slowness was observed after guest reset. Once they completed performance was ok for a while but would later freeze / slow down.
Occasional GUI delays in Windows 11 guest VM observed when all CPU threads were 100% in Task Manager. (applicable for r7 4750u) And for r7 7700 but far less and CPU not 100%
This made me think of upgrading the CPU in particular and the RAM as headroom.
Can you get both CPUs and try, and then return one?
Sure, they are both in shipping. I need to figure out how to properly clean thermal paste if I will be testing both. I was hoping to decide on one and return the other. Had to order to get a reasonable price while in stock.
In particular Windows Server VM freezing … Occasional GUI delays in Windows 11 guest VM
I feel like 2Core/4GB is minuscule for windows, even for an idle server.
how to properly clean thermal paste
Cotton pads or a piece of cloth and isopropyl alcohol
200w imposed by the InWin Chopin Max case
BTW, is this already set in stone? I’d rater pick some slightly bigger yet still small and inexpensive case, like NR200 (saw ~40$ used from ebay) and slap a proper PSU and Cooler
Overall I’m inclining to 7950x. Single core perf wouldn’t buy you much if there are many contenders competing for this single core :). Maybe 9900x would be just enough, but that’s only you will be able to find out, empirically. It has some architectural advancements, like more of AVX512, but I don’t know if any of your workloads can benefit from that, it doesn’t sound like massively parallel number crunching (well, maybe deep packet inspection could do something with it)
For now it is the best that I could find to be easy to carry and not overly expensive as I have to move around. If that was not the case NR200 and peerless assassin 120 all the way!
I have also considered Minisforum BD790i / BD795i SE to go with the InWin Chopin Max but unfortunately their BIOS / firmware support is lacking.
