X299 and 7980XE in 2024

[mackerel]

I know, the 7980XE isn't exactly new. It was released in 2017, over 6 years ago. But my X299 system went 7800X, 7920X and now 7980XE. 6 core 7800X was bought when it was just released. I ended up getting a 12 core 7920X to replace it in 2019. Now I've reached the end of the road, the 18 core 7980XE. Technically I can get newer generations of the same CPU, but this being the oldest generation helps keep the price lower.

Got it used from a UK shop. They have branches in many bigger towns and cities. Their website lists it at £200, but it wasn't in stock until a random check on Sunday. Whipped out my credit card and ordered it. Since it was in a non-local store they shipped it next day thus arriving today.

Simple CPU swap right? If only. After pulling my system out, I realised the size of the job ahead of me. It has a Noctua cooler. The fan has to be removed to unscrew the heatsink. I can't unclip the fan with the GPU obstructing one of the tabs. I can't reach the PCIe slot release tab without removing all ram from one side of the CPU. I also have a vertical M.2 slot in front of the ram. All that had to go to extract the CPU. With that done, I plopped in the new one after giving both the socket and new CPU a visual check. A quick jiggle of the CPU in the socket before engaging the retention mechanism. Then I had to repeat all the above to put everything back in. Plugged in the main unit, hit power and... nothing. Fans spun up, but no screen output. I checked all cables were in place. Yes, I tried turning it off and on again. Multiple times. Nothing.

The unit is normally in a corner of my room so I can't see anything on the motherboard. I moved it over to my TV and tried booting there. Red LED: CPU. I had to do the whole extraction process again to reach the CPU. Took it out. Blew on the contacts. Still looks fine. Put it back in. To save time, I didn't put a cooler on, and swapped the 4070 for a 1650 so I don't have to worry about the power cable during diagnosis. This time, I saw red, yellow, white LED. Success? Power off in case the CPU got too hot. I rested the cooler on top (with the old paste still on it) and let it boot longer this time. Red, yellow, white, green, and display output! YES!

Let it get to Windows. Seems fine. Ran stress test in CPU-Z for a moment. Ok. Ran stress test in Aida64 for a minute or so. Still ok. Ran Prime95. Still ok. Remember, this is just with the heatsink, no fan! Peak temps didn't go above 60C in this short time, although I could feel the heatsink getting warm. So must have been a bad connection the first time. Slightly concerning but if it works now, it'll do. Power off, put all the normal hardware and now I'm running it like normal back at my desk.

I've turned XMP on. All my ram is detected. All my PCIe devices seem to be working normally. Onto stress testing. I found Intel's Processor Diagnostic Tool and that passed. Currently I'm running real work equivalent to Prime95 small FFT. It includes error checking so I'll know if anything is wrong. Peak temps 71C so still fine.

While that runs, I have other things to do. When I return I'll get onto benchmarks to compare to one game "before" results and see what impact this has. I hope it helps otherwise this is a bit pointless

 

[mackerel]

I ran out of time to do benching for the day so it will have to take place tomorrow.

I couldn't resist firing up Cities Skylines II because that was the driver for me getting the CPU. While much has been made of the game graphical performance early on, the bigger limitation to longer term play is the simulation speed. It is ok with smaller cities but large cities slow to a crawl meaning seeing the impact of any changes takes forever.

I came up with a method to manually benchmark the simulation speed. I observed how fast the in game clock runs vs real time. I used 3 of my own cities to test, populations around 80k, 135k and 250k. I did pre-testing on the old CPU to check if the graphics settings affected simulation speed (it didn't), and if XMP had any impact (possibly tiny, but margin of error).

Note I only did one run on 7980XE so no double checking yet.
80k pop - time to progress 30 minutes in game: 7920X: 22 - 23s. 7980XE: 25s, may be something else happened or it really is a little slower.
135k pop - time to progress 30 minutes in game: 7920X: 25 - 28s. 7980XE: 26s, in the same range
250k pop - time to progress 10 minutes in game: 7920X: 46 - 52s. 7980XE: 31s, a big improvement

I was starting to get worried the game might not scale to many threads when I saw the lower population results, but it really does seem to help at the higher population.


The only other pre-testing I did was Cinebench 2024 and Y-cruncher. Those will follow later.

 

[mackerel]

Done some more benches.

7920X vs 7980XE

Cinebench 2024: 805 vs 1111 or +38%

Y-cruncher
25m: 0.451 vs 0.331 or +36%
1b: 27.437 vs 21.096 or +30%
2.5b: 78.173 vs 60.118 or +30%

I now have 50% more cores, but the clock when all are active will be lower. According to Anandtech's review when the CPU was new, 7980XE runs 18 cores at 3.4 GHz, and 7920X runs 12 cores at 3.8 GHz. Both for non-AVX loads, and both Cinebench and Y-cruncher do use AVX to some degree.

I don't expect to post much more to this thread unless I see anything "interesting" or get specific requests.

 

[MaddMutt]

Having benched both processors, I have to ask if you delidded them?

 

[mackerel]

I have a delid tool from when I used it on the 7800X, but haven't done the 7920X. I might do that one at some point as the resale value isn't much, but only if I feel like I want to OC it hard. I don't have any plans to do the 7980XE even though I do have a hot core. For normal use it doesn't matter.

Might be a good time to say I just bought another X299 mobo. It's a bit of a gamble as it is an Acer OEM board as to exactly what it will do, but the price was low enough to be interesting. I think I have everything else I need to build a system.

 

[MaddMutt]

You know - the prices on the 7xxx (x299) cpus are rock bottom. You could grab several - 7640x, 7740x, 7820x - for about $150 total and work on completing the x299 cpu collection <- ROFL
I’m not sure how good the BIOS is on that Acer MB. I know the Asus R6A/Evga Dark allow a wide array of BIOS options.

 

[magellan]

I don't know if I would put any money into older tech now, DDR4 and PCIe 3.0 are dead-end tech, but maybe it all depends on your use case.

 

[mackerel]

For my interest area X299 still has significant value. It has full fat AVX-512 which is absent in consumer tier CPUs. Current Intel and AMD offerings are weaker, although newer CPUs might overcome that weakness through clock. Also the quad channel DDR4 means it is still comparable to DDR5 systems in that area. To get comparable performance to my Intel 7920X right now on desktop I'd have to get an AMD 7900X which would be much more expensive.

As for filling out the collection, pass. This is simply "because I have everything else" to build a system already. It is only the mobo I'm missing and the Acer was cheap enough to be worth a go, even if it may be more limited as an OEM model. A few years ago I did want the 7740X as I wanted to try for quad core world records but more modern quad would easily pass it now.

 

[Railgun]

Got it used from a UK shop. They have branches in many bigger towns and cities.

Oh? Who's that?

 

[mackerel]

Oh? Who's that?

Cex. If not in your local store they also deliver which is how I got this CPU.

I often check out what they have if I'm passing. Selection in store can be limited and they don't do motherboards. Maybe too much risk for them? But they generally offer 2 year warranty so where pricing is competitive it is a safer choice over other buying channels.

 

[freeagent]

To get comparable performance to my Intel 7920X right now on desktop I'd have to get an AMD 7900X which would be much more expensive.

Just a quick google search shows even a 5900X leaving your new CPU in the dust?

Not that it matters in the slightest.

Enjoy your new toy

 

[mackerel]

Just a quick google search shows even a 5900X leaving your new CPU in the dust?

Keep it in context of the whole paragraph of my response. I was talking about use cases focusing on quad channel ram and AVX-512. Basically nothing mainstream before AM5 would keep up. AM4 has no chance. For lightweight uses like rendering or general lower thread counts like some gaming, many other CPUs could be faster. AMD's 7900X is closest to Intel's 7920X in that it has about the same ram bandwidth, and while it has a weaker AVX-512 implementation it is made up for by higher running clocks. For light workloads like Cinebench, yes, the 7900X would probably be a lot faster. But I don't play Cinebench much

 

[EarthDog]

Like the 2.9% on Linux, Mack.

 

[mackerel]

Like the 2.9% on Linux, Mack.

Yes but this is my thread

 

[Railgun]

Cex. If not in your local store they also deliver which is how I got this CPU.

I often check out what they have if I'm passing. Selection in store can be limited and they don't do motherboards. Maybe too much risk for them? But they generally offer 2 year warranty so where pricing is competitive it is a safer choice over other buying channels.

I must have walked past that 100 times and never gave it a second look. Figured it was just a second hand phone shop. Guess now I'll have to pop in.

 

[mackerel]

I must have walked past that 100 times and never gave it a second look. Figured it was just a second hand phone shop. Guess now I'll have to pop in.

Yeah, they have the wall of phones/tablets amongst other things. Don't expect too much but doesn't hurt to look. In my local store, there's usually a few random CPUs, a handful of SSDs, and a wider selection of GPUs. Some used 8TB HDs tempted me a bit at around £100 each, but I'm not desperate to get more space this moment. Also a variety of console hardware and games, including some retro. #notsponsored

 

[mackerel]

Main system just BSOD with "system thread exception not handled". A quick google suggests it could be hardware or driver related. Could it be the new CPU? I also updated to the latest Nvidia driver today.

Pretty sure the CPU itself is compute stable, as I left it running overnight on Prime95-like tasks. BSOD happened while I was looking at cat photos I took while looking for something else. So easily distracted.

 

[unsafesteagle]

id be stuck double checking voltage memory and c state config

thats real nice powerful cpu for its day

 

[magellan]

Were all the Skylake X CPUs using TIM instead of solder for their interface to the heatspreader? It seems like an odd decision for Intel to make considering they were HEDT.

 

[mackerel]

Were all the Skylake X CPUs using TIM instead of solder for their interface to the heatspreader? It seems like an odd decision for Intel to make considering they were HEDT.

7000 series was paste. 9000 series was soldered. For normal use they don't get that hot.