#Cpu for new build

1 messages · Page 1 of 1 (latest)

rigid helm
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Hello everyone. I was curious about what cpu to choose from. I will be mostly focusing on gaming, so I know that the ryzen 7 9800x3d is the best choice but it just isnt available where I live, is completly sold out. Not to mention it is quite expensive, and would make choosing a gpu harder for my budget. I though of it's predecessor, the 7800x3d. It seems to be the second best cpu for gaming, but why is that? if I go to like cpubenchmark.net it loses to the 9700X for instance or even the 7700X

Can anyone help me? I'll also probably ask about the gpu next, but cpu is the first concern

magic pivot
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I think it has to do with how the 7800x3d and 9800x3d split their 3d V-cache, compared to other chips given that the 3d V-cache isn't as useful for non gaming tasks.

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I'm not entirely sure but I'm pretty sure that's why

tranquil chasm
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7800x3D simply can’t boost as high due to thermal constraints, so productivity performance gets hampered.

magic pivot
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This list is good

sour karma
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What resolution will you be gaming at and what is your budget?

rigid helm
rigid helm
# magic pivot

im not into the amd market, any ryzen why r7 7800x3d would be better than r9 7950x3d? more numbers usually mean better ahah

rigid helm
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and the budget is around 1400-1500 euro. Being in europe the prices differ a lot from america

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update: I saw a deal to good to pass on and I'm gonna buy the 7800x3d

sour karma
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The resolution of your monitor will determine what resolution you can game at. If you have a 1440p monitor then you have the option to game at that resolution

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7800x3d is a great option

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If you can get a reasonable price

rigid helm
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thanks, going to buy it now!

mint kernel
# rigid helm im not into the amd market, any ryzen why r7 7800x3d would be better than r9 795...

7950X3D isn’t faster than 7800X3D for gaming because of how the CPUs were designed and because how games don’t usually scale with core count. 7950X3D has two separate dies unlike the 7800X3D. You can think of it like two factories that are across a river from each other but there’s a bridge connecting them. The two factories (7950X3D) can produce more than a single factory (7800X3D) but if a part can be built using only one factory (video games) then there’s no real benefit to the second factory. Additionally, for small to medium size things it’s way slower to send something across the bridge to the other factory than it is to keep it in house, so the extra capacity of the other factory can be detrimental in rare cases. But of course, if you’re building something really big, two factories with typically be better than one even with the bridge (CPU intensive tasks that scale with core count). Not a perfect analogy but it should be suitable to give you a basic idea

magic pivot
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It has to do more with how the 3d cache works

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Since each core has one on the 7800x3d and only every other core does on the 7950x3d

mint kernel
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Really?

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That would explain it

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But I don’t get it from a chip design standpoint

magic pivot
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There's often a lot of limitations around it

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The last time I did hobbyist level chip design was a while ago

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So I probably couldn't explain

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But essentially both chips have the same number of cores with 3d V-cache

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And most games only use 8 cores

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At most

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The 7950x3d essentially has 2 chips on it, one being what is essentially another 7800x3d on it, and one without the 3d v cache, that can reach higher clock speeds

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The reason It performs worse is because the scheduling between the different chips isn't always perfect, and other small things like that

magic pivot
# magic pivot

The performance on the 7800x3d and 7950x3d are almost the exact same, with only a 2.9 average fps difference

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Essentially a 3d V-cache makes the chip have a slower clock speed, so the 7950x3d has 2 chips.

tranquil chasm
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The presence of 3D Vcache doesn't necessarily cause the reduction in clock speed per se. It was mostly the placement. 7000x3D was limited in clock speeds for temperature reasons because the v cache was placed on the top of the cores, and acted as an insulator for the cores. 9800x3D overcame this by placing the v cache under the cores, so the thermal issue was resolved, which is why the 9800x3D can have much higher boost clocks/power consumption over the 7800x3D.

sour karma
magic pivot
tranquil chasm
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The mere presence of the v cache isn’t what causes the reduction of clocks. It was the placement/location of the cache.