1. Arachnotronic said he would take 7900x over 7920x and then only other alternative would be 7980xe. This makes no sense, because either you care about number of cores, in which case 7980xe is the best possible chip and in extension you have to consider 7920x to be better choice than 7900x. Or you dont care about the core number that much, in which case its totally OK to take 7900x over 7920x, but then again why not apply the same rules to 7960x and 7980xe? You dont mind 2 less cores with 7900x, but you do with 7960x?
I understand the allure of 7980xe, i would buy it myself over any other alternative, if i was willing to pay the money. But there is no way one can rationally justify those choices he said he would make.
I was explaining a post someone else made. Something that comes up in SL-X or TR threads, someone saying in regards to a CPU only a 2 Cores larger that it is only 2 cores and no one would notice the difference. It was a joke that it meant you work your way down to Pentium with that thought process. But it was part of the point, once you get beyond 4 cores you are really working on a different playing field in terms of use case and the reality is chances are at each step there is probably a measurable difference with an extra 2c4t. Otherwise you probably shouldn't be looking at CPU's with high core counts anyways. This portion was actually in support of a CPU like the 7920x. If you are running something that utilize a 7900x, then you are probably running something that would benefit from 2 more cores.
2. What MCC power usage? Do we really know its that much higher than LCC, or do we just assume that it has to be cause of more cores? The base clock is completely irrelevant, the all-core turbo-clock is just 200 MHz lower against 7900x (3,8 to 4Ghz). You want to tell me those additional 200Mhz make the extra 2 cores not worth it? Tough to believe.
There is a poster on Overclock.net from Netherlands, who ran his 7920x at 4,6Ghz and 1,2V. Not that far off from 7900x again, is it? Per info from him, it actually looks like MCC chips dont suffer from the TIM issue as much as LCC chips, probably cause of the bigger die area.
Bottom line, 7920x is far from the worst CPU in the line-up. Maybe to you, based on your personal criteria/preferences, which is absolutely fine, but there will be many people who will see it other way.[/QUOTE]
I have stated before, power usage on Intel or AMD CPU's is pretty linear. The difference is that on the AMD Threadripper side by having 2 dies you can take the power of each configuration as we know from the Ryzen lineup while keeping an eye on clock speed and just double up. This doesn't work as well on SL-X in regards to LCC due to a bit of large die overhead in comparison to lets say a 4c die (7600/7700). There was a measurable difference between 7900 and 7820 but the 7820 was still more power than a doubled up 7700 at the same clock speed. That the 7800 was more than 50% more than a 7700. Meaning that there was a power overhead regarding the die with as many cores as it had whether or not those cores were disabled. This should follow with MCC that the power usage of a 7920x should still be higher than the 7900 then the 7900x is over a 7820. You could be right and the larger die leads to better thermal transfer making it easier to not spike the CPU temp like what people were seeing on LCC but that won't remove the fact that the power usage will still be even more through the roof and that you will have that much more power to have to dissipate at any given clock speed. Most of this is conjecture based on the information on hand we will have to see when it's released.
But I didn't just magically make up the idea that the 7920x isn't going to be considered a great CPU in the lineup. I just parroted reasons others have stated. At stock the 7900 is going to have such a clockspeed advantage that in tasks that utilize the cores well the 7900 will be as strong or maybe even stronger even though it has two more cores. It should have less OC potential. It is more expensive. Other than an extra 2c4t for VM work there would be little that the 7920 would do better than the 7900. Where as a 7940x would have 40% more cores with similar clocks to the 7920 with the same OC potential, same thing with the 7980xe with 80% more cores and the 7960x in between. If you can't afford a 7940x you would be better off with the 7900x.