AMD - Piledriver chitchat

[DanceswithUnix]

I believe part of the pad size issue is that silicon and package substrates expand at different rates when heated, so you need a larger pad to maintain the connections when the chip heats up. Using an interposer removes the thermal stress issues so you can use micro-bumps on the actual chips.

I think the main issue is the big power fets required to swing a comparatively high voltage into the capacitance of an off chip connection at GHz speeds.

However, I doubt that making a smaller chip AND an interposer would be significantly cheaper than making a slightly larger with slightly larger bumps/pads - after all, if you're pad-limited on the smallest chip you can make you can just cram more transistors into it...

Which is how chipsets got integrated graphics and prefetch caches back in the Athlon/P4 days, it was that or waste the space

[CAT-THE-FIFTH]

Rumour that Zen APUs might be using HBM:

http://www.bitsandchips.it/english/5...kaged-by-amkor

[CAT-THE-FIFTH]

More details about AM4:

http://www.bitsandchips.it/english/5...have-1331-pins

Future AMD AM4 Socket will be µOPGA, and it will have 1331 pins. A LGA solution will be used for Opteron Zen CPUs.







AM4 solution will have the virtue of putting together the plus points of the three actual AMD sockets: AM3+, FM2+ and AM1.

Like AM3+ Socket, AM4 will be able to support 140+ Watt CPUs and APUs. Like FM2+, AM4 will be able to support powerful integrated GPUs. Like AM1, AM4 will allow to realize budget mainboards, as much as high end mainboards: AM4 CPUs and APUs will have an integrated FCH, but a lot of features can be added thanks to external chipsets (more PCI-E lines for multi GPUs cofigurations, M.2 slots, etc).

[DanceswithUnix]

140W seems odd for a socket targetting up to date silicon processes. You need a big die to get rid of that sort of heat. It would also line AMD up for quips about still running hot as always regardless of whether it is true.

[shaithis]

140W seems odd for a socket targetting up to date silicon processes. You need a big die to get rid of that sort of heat. It would also line AMD up for quips about still running hot as always regardless of whether it is true.

maybe for server/workstation parts with tons of cores.

[DanceswithUnix]

maybe for server/workstation parts with tons of cores.

Possibly, in the same way that Xeons can have sky high TDP ratings. I wouldn't want to see that on consumer boards though, I think the 100W limit on FM2 motherboards has been useful in keeping costs down, and you don't get the aggro of hunting through motherboard compatibility lists to see if your 125W cpu is on the approved list like you do with AM3+ boards where not all 125W boards can handle an 8350.

[CAT-THE-FIFTH]

It looks like Zen has different cooler mounting points when compared to AM3 and FM2+ it appears:

http://www.bitsandchips.it/english/5...-older-sockets

[DDY]

I was hopeful that AMD would choose something square

I wonder if the mounting bracket clip position is the same or at least retains some compatibility with the older socket.

[kalniel]

There's an interesting musing at Eurogamer about possible refreshes of the current consoles:

http://www.eurogamer.net/articles/di...sony-making-it

It's interesting because it's unusual for consoles to be refreshed so soon in any kind of significant performance way, but it seems MS are not happy giving up performance to the PS4 so are planning one, and Sony therefore are responding.

It's relevant because these are such big orders that AMD is going to be prioritising them, and possibly engineering things in future APU/GPUs with console in mind.

Could we see Zen as a console chip first?

[CAT-THE-FIFTH]

I think we might just see the same CPUs,but running at a higher clockspeed,with faster GPUs.

If they start mucking around with a much different CPU in makes things more complicated as opposed to going to faster version of the current GPUs based on a slightly newer version of the uarch. I expect the newer consoles to have GCN1.2 based GPUs.

[scaryjim]

It looks like Zen has different cooler mounting points when compared to AM3 and FM2+ it appears

Shame, I was kind of hoping my WC kit would be compatible. Maybe I can mod the brackets....

... I wonder if the mounting bracket clip position is the same or at least retains some compatibility with the older socket.

The article CAT linked says they will, and with them only just having updated the Wraith cooler it would make a lot of sense for them to keep some degree of compatibility...

[scaryjim]

I think we might just see the same CPUs,but running at a higher clockspeed,with faster GPUs. ....

Reading up, I kind of favour the interpretation that we might get a PS4 Slim with extra 4K media capabilities via HDMI 2.0.

Sony wouldn't need to change the configuration of the SoC at all, but could upgrade the cores to Puma and Polaris. The various compression techniques that came in with GCN 1.2 would mean the existing memory size and bandwidth would probably be sufficient, and the architectural improvements would give a slight performance bump at much lower power draw. The extra features available in the updated GPU could be exposed through the API in such a way as to make them only usable as an enhancement, not as a core part of an engine, so programmers could know they were targeting the same platform but with a couple of extra bells and whistles if the game is played on a Slim. Plus I'd be amazed if the latest versions of GCN didn't include some optimisations for VR to improve latency on lower-performance platforms.

[DanceswithUnix]

The article CAT linked says they will, and with them only just having updated the Wraith cooler it would make a lot of sense for them to keep some degree of compatibility...

That would seem backwards. I would prefer to see a 95W TDP cap on the platform, and make the cooler smaller given that ITX is becoming so popular.

[scaryjim]

That would seem backwards. I would prefer to see a 95W TDP cap on the platform, and make the cooler smaller given that ITX is becoming so popular.

I believe the wraith cooler is being bundled with 95W CPUs anyway, so even if they capped the platform I could still see them maintaining compatibility with the older cooler mounting.

I suppose the question is whether they'll continue using AM4 as an entry level 1P sever platform as well as a consumer platform, like they did with AM3. If they do then we'll likely see higher TDP CPUs on the consumer side to push the performance up. I've owned smaller AMD stock coolers in the past, and Lord help me they were loud. If AMD could engineer a small, effective, quiet cooler I'd be all over that. So far they haven't shown any great strides in that direction, and some degree of backwards compatibility for people who've invested in third-party coolers has to be a good thing, surely? They've been talking up targeting the enthusiast market with some of the early Zen releases, at which point they must know most people won't be using the stock cooler anyway....

[DanceswithUnix]

Reading up, I kind of favour the interpretation that we might get a PS4 Slim with extra 4K media capabilities via HDMI 2.0.

Sony wouldn't need to change the configuration of the SoC at all, but could upgrade the cores to Puma and Polaris. The various compression techniques that came in with GCN 1.2 would mean the existing memory size and bandwidth would probably be sufficient, and the architectural improvements would give a slight performance bump at much lower power draw. The extra features available in the updated GPU could be exposed through the API in such a way as to make them only usable as an enhancement, not as a core part of an engine, so programmers could know they were targeting the same platform but with a couple of extra bells and whistles if the game is played on a Slim. Plus I'd be amazed if the latest versions of GCN didn't include some optimisations for VR to improve latency on lower-performance platforms.

Changing the CPU core is bound to break something when you are optimising for a platform like a console. If you just add in a call so that a program can request a faster CPU clock, then old programs behave identically to before but ones that know about the new platform can ask for a bump (and choose to run slower on the old platform if they want or just put up an error screen if they can't). Similar with the graphics, if it isn't utterly identical then it isn't compatible. Requesting a bump in speed or number of SPs might be possible though.

They've been talking up targeting the enthusiast market with some of the early Zen releases, at which point they must know most people won't be using the stock cooler anyway....

Yeah, I'm not concerned with the stock cooler so much as the mounting footprint. Look at an AM2+ ITX board, there is a massive wasted space around the CPU for cooler fittings.



If they could shrink the CPU footprint, now is the time to do it.

[DanceswithUnix]

Well I wasn't expecting any real performance improvement from the upcoming Bristol Ridge, but it looks like they managed to drag some more mips from somewhere (most likely from better power management)



(from http://semiaccurate.com/2016/04/05/a...a-series-apus/)