AMD - Zen chitchat

[scaryjim]

... Heat is linear, power is not. So when DwU said "Stacking something on top of the CPU stops the heat getting out" saying yes is entirely correct as the heat at source would not be the same as the heat at the external surface, when DwU said "under stops power getting in" it is also entirely correct to say no as power is a binary, you either have it or you don't. ...

This isn't an attack on you personally - I'm pointing out that the way you originally made your point did not clearly communicate your intention. There appeared to be a clear implication that additional silicon below a CPU die would not impact power delivery.

As it happens, now you've clarified what you were trying to say I also happen to disagree with your point. In both cases the additional silicon will add resistance to the movement of either heat or power. It will be harder for heat to escape, it will be harder for current to get in. In neither case will the movement either be completely stopped, or completely unimpeded.

ADDENDUM:

... Is that clear enough for you or would you like to attack me personally some more while completely ignoring someone who said that what you said is "purely a figment of your wonky imagination" and that they "don't need you to tell us that".

I hadn't actually seen that reply - I have a limited amount of time for forums and follow some threads closer than others. Now you've brought it to me attention I'll go and have a proper look...

[Corky34]

This isn't an attack on you personally - I'm pointing out that the way you originally made your point did not clearly communicate your intention. There appeared to be a clear implication that additional silicon below a CPU die would not impact power delivery.

As it happens, now you've clarified what you were trying to say I also happen to disagree with your point. In both cases the additional silicon will add resistance to the movement of either heat or power. It will be harder for heat to escape, it will be harder for current to get in. In neither case will the movement either be completely stopped, or completely unimpeded.

And that's why i said that's what TSV's are for, they do not add resistance to the movement of power anymore than traces, power lines, or bumps do, whereas *AFAIK there's no way you can't add thermal resistance when you increase mass.

* I know there's been laboratory tests of exotic types of cooling between transistors but i don't think anything has reached production.

[scaryjim]

And that's why i said that's what TSV's are for, they do not add resistance to the movement of power anymore than traces, power lines, or bumps do ...

No, but they still add to the resistance - it adds at least one more set of bump and transitions, which means you get power loss over those additional components. So either you have to drive more power to the socket, or use less power in the CPU. In pretty much the same way that an extra slice of silicon means you get increased thermal resistance, so you have to use beefier cooling to maintain the temperature gradient and get heat away from the CPU.

You seem to be convinced that the thermal effect will be significant while the electrical one won't. I'm not so sure...

[Corky34]

Yes but any electrical connection from one point to another adds resistance, traces, power lines, and bumps all add resistance and they're all accounted from when designing the power requirements, however that's besides the point as the original proposition was that it stops power getting in, not that it increases resistance.

Increased resistance, not that that's typically what happens when using TSV's as resistance actually goes down due to the shorter distances involved, however increased resistance can and has been taken account of when designing your power delivery circuitry for decades.

Whereas you can stop, or at least drastically reduce, the escape of heat to such a point where it causes failures.

[scaryjim]

... the original proposition was that it stops power getting in …

As I said, I read that comment as hyperbole. I'm pretty sure DwU wasn't saying that it's impossible to get power to a CPU that's stacked on top of another another piece of silicon, he's not an idiot...

… not that that's typically what happens when using TSV's as resistance actually goes down due to the shorter distances involved, however increased resistance can and has been taken account of when designing your power delivery circuitry for decades.

You can engineer around heat transfer as well though. I still don't understand why you want to treat the heat problem differently...

Anyway, it's all about those engineering compromises. If you have chips spread over a wider area you can use larger traces which have lower power loss. Once you concentrate all your power delivery into a small area you start making compromises on what can happen - you have to use smaller traces and bumps which have greater power loss, you have to add additional bumps and connections between dies which increase power loss, and you cram a lot more current through a smaller area - which increases power loss. It all adds up.

And while you can engineer around some of that, ultimately you can't beat physics, which means the end solution may well be designing chips that run at lower power and generate less heat - which is exactly what DwU said in the first place.

[DanceswithUnix]

Yes but any electrical connection from one point to another adds resistance, traces, power lines, and bumps all add resistance and they're all accounted from when designing the power requirements, however that's besides the point as the original proposition was that it stops power getting in, not that it increases resistance.

Blimey, I know you have to be careful what you say on the Interwebz but this surprises me. Using the word "stop" was with hindsight not optimal, but if I wanted to say it was a perfect insulator I would have been a lot more wordy.

Really, it was a throwaway comment that I could see issues with using stacking with a CPU on desktop machines which wouldn't be an issue on laptops. Consider the grief Intel have had in recent years because the thermal compound they used wasn't as good as a solder when both were designed for thermal conductivity. So how well is introducing a semiconductor layer between the CPU and heat spreader going to go?
I wrote a big long thing on power delivery here, but now I've deleted it because I just don't have the time to get into another discussion. But really, power traces are considered inductors, they are far from a binary issue.

("Post Quick Reply" sometimes seems such an inappropriate button name )

Edit: Mostly my thoughts were that laptop users wouldn't see an issue as at 35W none of this matters let alone the 15W you often get in laptops. But I prefer desktops and don't like anti desktop tech.

[Corky34]

And IMO i treated it as a throwaway comment, hence why i kept the initial answer brief, but apparently scaryjim took exception to my yes/no answer and said that i really needed to work on clear communication and that i was naive.

Seems i can't win either way, one of you berated me for a being too brief and the other for being overly specific.

[krustylicious]

Speculation that the ryzen 3xxx series will launch on the 7/7, for me that makes a ton of sense;

a)allows for 1x and 2x inventory depletion.
b) allows for 8/12c TR inventory depletion.
c) limits chip cannibalisation.

Also it allows Rome to come out before that. Plus it gives them time for another spin to iron out bugs. More so on the Io chip than anything

[Xlucine]

Whelp, I'm up for a new CPU. With the imminent launch of zen2, my plan is to go with a zen-based athlon for now then upgrade (either to zen 2, or a cheap zen+) in a few months. I'd like the stand-in to provide similar performance to my current i5 (haswell 4C4T), and be as cheap as possible (duh) - do you guys think a 200GE would cut it? "Similar performance" means not tanking fps in not-brand-new games (doom, unmodded skyrim) - it'll be a bit slower (similar IPC, less speed), but the same number of threads (and older games probably don't multi-thread all that well)

[Bagnaj97]

Whelp, I'm up for a new CPU. With the imminent launch of zen2, my plan is to go with a zen-based athlon for now then upgrade (either to zen 2, or a cheap zen+) in a few months. I'd like the stand-in to provide similar performance to my current i5 (haswell 4C4T), and be as cheap as possible (duh) - do you guys think a 200GE would cut it? "Similar performance" means not tanking fps in not-brand-new games (doom, unmodded skyrim) - it'll be a bit slower (similar IPC, less speed), but the same number of threads (and older games probably don't multi-thread all that well)

I'd spend a little extra and get a Ryzen 3 1200 because 4C4T rather than 2C4t should give a significant performance boost in newer games. https://www.amazon.co.uk/gp/offer-listing/B0741DN383/ Used ones show up on Amazon warehouse for <£50 sometimes.

[DanceswithUnix]

I was in a similar position a while back. 200GE is 4 threads not 4 cores, so I suspect that isn't up to the task.

4690K is still a pretty capable chip. I'm using a 2200G which is quad core and seems reasonably quick but in the VR headset just runs out of threads.

I can try it in flat screen Doom when I get home, but I suspect it will be fine. It handled Elite in 1440p, levelling up a WoW character up to level 20 which are quite modern. Can't remember what else I have played on it, but it hasn't stuttered yet on a standard screen. I baulked at £80 for the 2200G, but when I upgrade my main rig it would be easy to re-purpose.

If I were choosing again, the 2600 at £130 is a stonking deal and I would probably just go for that. Again, a capable chip that can easily find a new hand me down home, and would mean I could wait a bit for release day prices to drop and make sure the BIOS bugs are shaken out before getting Zen 2. Even this close to Zen 2 release I am slightly twitchy to buy one so I can get the VR headset out, but it has been a bit of an expensive month.

[Xlucine]

I'd spend a little extra and get a Ryzen 3 1200 because 4C4T rather than 2C4t should give a significant performance boost in newer games. https://www.amazon.co.uk/gp/offer-listing/B0741DN383/ Used ones show up on Amazon warehouse for <£50 sometimes.

Good idea - there was a new one for £53 with p&p, so that's a pretty cheap upgrade on the 2C athlon.

I was in a similar position a while back. 200GE is 4 threads not 4 cores, so I suspect that isn't up to the task.

4690K is still a pretty capable chip. I'm using a 2200G which is quad core and seems reasonably quick but in the VR headset just runs out of threads.

I can try it in flat screen Doom when I get home, but I suspect it will be fine. It handled Elite in 1440p, levelling up a WoW character up to level 20 which are quite modern. Can't remember what else I have played on it, but it hasn't stuttered yet on a standard screen. I baulked at £80 for the 2200G, but when I upgrade my main rig it would be easy to re-purpose.

If I were choosing again, the 2600 at £130 is a stonking deal and I would probably just go for that. Again, a capable chip that can easily find a new hand me down home, and would mean I could wait a bit for release day prices to drop and make sure the BIOS bugs are shaken out before getting Zen 2. Even this close to Zen 2 release I am slightly twitchy to buy one so I can get the VR headset out, but it has been a bit of an expensive month.

Going straight to a high end ryzen is tempting, but I'm fairly certain that zen2 will be worth the extra outlay on the stand-in CPU (or will cause price drops in high-end zen+ enough to make up for the extra cost). I'm happy with the performance now, so if the stand-in matches my i5 then I'll have plenty of time for zen2 to stabilise before buying

[scaryjim]

... if the stand-in matches my i5 ...

When I crunched the numbers for my step-son's computer 18 months ago istr that a Ryzen 3 1200 had better performance than the i5 3570k, which was the most likely upgrade option on his existing platform - which is why I opted to do him a full rebuild rather than a quick upgrade.

Worth remembering that all Ryzens can be overclocked on suitable motherboards (and since you're thinking Zen 2 I'm assuming you'll go for a higher end board), so if you're up for a bit of tweaking you should get very close to the stock 4690k, and even at stock you'll find you're not losing that much. I went for the 1300X for my step-son because he's not an overclocker...

[Xlucine]

When I crunched the numbers for my step-son's computer 18 months ago istr that a Ryzen 3 1200 had better performance than the i5 3570k, which was the most likely upgrade option on his existing platform - which is why I opted to do him a full rebuild rather than a quick upgrade.

Worth remembering that all Ryzens can be overclocked on suitable motherboards (and since you're thinking Zen 2 I'm assuming you'll go for a higher end board), so if you're up for a bit of tweaking you should get very close to the stock 4690k, and even at stock you'll find you're not losing that much. I went for the 1300X for my step-son because he's not an overclocker...

Yep - Asus TUF B450M-plus gaming. Seems to be one of the best available in MATX (except the -pro model, but that doesn't have the GPU in the first slot which is not optimal in my case).

The cooler doesn't look like much next to my old intel stock cooler - both around the same heatsink dimensions, except the intel one has no nice-looking shroud and braided cable, but does have a cup-shaped bit of copper in the core, and is intended to cool 91W of heat rather than 65W. Mounting the AMD one was a bit disappointing - the screws were hard to line up with the backplate, and they squeaked a lot as they went in, and you had to remove some plastic from the motherboard that seems to only be used to mount the top end wraith cooler (surely those users would want the better mounting pressure that comes with screwing together bits of metal?). There was also a very thick layer of thermal paste on the heatsink, so I might try a better application of paste later to see if it improves matters.

One downside of the 1200 over the 200GE - first gen ryzen ram compatibility! I forgot to check, so the ram I have is on the approved list for second gen ryzen but not first. I'm fine if it doesn't run at the full speed (still an improvement on 2133 MHz DDR3), but hopefully it boots tomorrow!

[DanceswithUnix]

Y
One downside of the 1200 over the 200GE - first gen ryzen ram compatibility! I forgot to check, so the ram I have is on the approved list for second gen ryzen but not first. I'm fine if it doesn't run at the full speed (still an improvement on 2133 MHz DDR3), but hopefully it boots tomorrow!

That's interesting, though I'm not sure where the APUs stand in that as the cores are supposed to be 1st gen but as a later product they may well have tweaked bits on it, but you probably wouldn't have been any better off. I'm running my 3200 ram at the top rated speed for the 2200G APU which is 2933.

I'm running my 3200 ram at max speed the 2200G is rated at which is 2933.

Happy booting, hope it goes well.

[Xlucine]

All booted fine, other than my wifi card deciding it didn't like its new home (probably because it's an intel chip). Ram decided to run at 2.4 GHz, which is fine for now

The boost behaviour is not what I'm used to. My old i5 would happily run at the full 3.9 GHz on all cores without overclocking, and at idle would clock down to ~800 MHz. The 1200 will only run at the 3.1 GHz base speed on all cores (which is expected, as it's a bottom rung part), but at idle it only drops to 2.6 GHz or so. I think it's using less power at idle though - previous idle temps were 36 C with a half-decent aftermarket cooler, but now it's just 28 C on the stock wraith stealth That little cooler has impressed me with what it can handle, and under load it's always under 60 C (compared to the intel chip hitting 79 C, with an aftermarket cooler)

I only ran 3dmark benchmarks, but in those it's impressed me - the CPU performance suggests than the 1200 beats haswell clock-for-clock. It's a bit slower in the CPU part of the tests (5% across the 3 versions of firestrike, 10% in time spy), but that's with the i5 running 25% faster! If I can match the 1300X clocks when I get around to overclocking then I should see a clear improvement with ryzen.

I also took the opportunity to re-paste my GPU, and saw a 4 C reduction in temp under load combined with a 600 RPM reduction in fan speed, so it's been a pretty successful rebuild