How did AMD make Zen 2 faster?

[Bofferbrauer2]

Pemalite said:

Bofferbrauer2 said:

The question to me is more on how it will be designed. Will it also be with an I/O chip and CPU chiplets like the Ryzen and Epyc chips or will it be build differently? How much cache will the versions in Xbox and Playstation have? What memory will it support? will it have SMT enabled or disabled?

It will likely be a single chip solution with a single Ryzen CCX and loaded up with GPU Compute units... Much like how AMD builds current APU's regardless of segment... A single CCX is relatively small, so it shouldn't blow-out chip sizes of the entire chip when combined with the GPU... Plus it allows Microsoft and Sony to take full advantage of smaller geometry sizes in the future when they become available at the fab.

It will then branch out to a chipset with memory controllers and so on.

GDDR6 is definitely in... Whether it will have extra memory controllers for DDR4 support remains to be seen, maybe in the Playstation 5's case.

Bofferbrauer2 said:

For the record, I'm expecting 8 cores at 3.2-3.35 Ghz. Efficiency tests showed that until then the power consumption was very low (below 50W) but rose pretty fast after that point. And the difference between 2.6 Ghz and 3.2 Ghz was only 5 W. Since this includes the I/O chip, which is the same chip as the X570 chipset, one can assume that one alone pulls about 10W just like it does as the X570 Chipset, so the CPU part would only be at 40W maximum at those clock speeds without any need for binning. I'm certain it will clock lower in some instances, but since the clock speed below 3.2 Ghz doesn't have much effect on it's consumption, I doubt it will be used much except when idling.

It is pretty much confirmed at this point that next-gen is having 8-ryzen cores.
Leaks have pegged base clocks of 1.6Ghz and boosting to 3.2ghz.

Cache wise... Zen+ APU's have 512kb of L2 cache and 1MB of L3 per core whilst the non-APU derivatives have 512kb of L2 per core, 2MB of L3 per core.

Zen 2 retains the 512kb per core, but doubles the L3 per core yet again to 4MB.

So total cache for an 8-core APU is likely to be 4MB of L2, 16MB of L3 if AMD keeps the APU L3 cache half of the non-APU chips and retains the historical L2 sizes.

They might introduce an L4 cache or blow out L3 sizes to assist the GPU, they might not as well. - Not enough information on this front yet sadly.

Bofferbrauer2 said:

As for the GPU, I expect something similar to the RX 5700, although not the same chip. I'm expecting more like 44CU with 2-4 CU deactivated for enhanced yields, and clocked a bit slower than he RX 5700 (somewhere about 1400-1550 Mhz) to limit power consumption to something a console case can dissipate without overheating (which is normally around or slightly above 200 W).

It won't be using the same GPU architecture... A derivative sure, but it's already been confirmed that the console GPU's will have deviated from the PC's GPU's.

It is likely to be the same situation the Xbox 360 GPU found itself in... It was based on the Radeon x1800, but took design principles from the Radeon HD 2900 and was something fairly unique.

Next-gen is based on Navi, but they have implemented more forward technologies like Ray Tracing, hence why it won't be directly comparable to any AMD GPU on the market today. (Which makes flops comparisons even more useless.)

Consoles can dissipate 300W~ of heat easily enough, PC coolers have gotten advanced and cheaper, consoles tend to rely on such developments.

On the RAM, GDDR6 is by far the most likely, but not the only option. HBM2, while probably too expensive, would also be possible, especially if one of the two wants to make it smaller than usual. And GDDR5X would technically also be an option.

But my question is also on the amount of lanes. If they come with odd amounts of RAM like 20 or 24 GiB and they're using GDDR6, then I'd hope they would also give the memory 320 or 384 lanes to connect them all at full speed. But somehow, I doubt it, especially if they come with 20 GiB.

The cache size will sure be interesting. They could increase it for efficiency, add an external large L4 cache otot, or make it smaller to get smaller, and thus cheaper chips with better yields. Wait and see, I guess.

PC's have still one advantage over consoles for heat dissipation: They're normally thicker, allowing for bigger exhaust fans. 80mm fans are pushing it for consoles unless you put them on the top/bottom (comparable to the side of a PC tower), which is generally not done, while even small, thin PC builds allow for at least some 120mm fan to be installed. So not sure if those 300W, outside of very short peaks, hold up. They might technically be able to dissipate 300W of heat, but you'd better play with earphones then as the smaller fans would be running at close to 100% then to achieve that.

For comparison's sake, the PSU of the PS4 was rated for 250W maximum and that was overkill, at no point the PS4 pulled over 180W even at stress tests. As a result the one for the Slim is only rated for 165W anymore despite the consumption reduction only being about 30% according to Sony. Even the One X PSU is only rated for 240W, and draws less than 180W under full load, so there's no way that comes anywhere near those 300W of heat to dissipate. The consoles are just not meant to do that.