Hardware bug in Skylake and Kaby Lake : Unsafe Hyper-Threading

[Lord Nicoll]

Well, I was wondering why even not overclocked I was getting erroneous crashes, I thought windows was just fucked up, I wonder is this it causing it. 

[MageTank]

2 minutes ago, Lord Nicoll said:

Well, I was wondering why even not overclocked I was getting erroneous crashes, I thought windows was just fucked up, I wonder is this it causing it. 

Highly unlikely, unless you are doing something very specific and niche. What are you doing while the crashes take place?

[LAwLz]

9 minutes ago, MageTank said:

That sad feeling when @LAwLz quotes nearly every post in the thread, except mine

I didn't feel like I could add anything to your post.

Feel better now that you're quoted?

 

5 minutes ago, Lord Nicoll said:

Well, I was wondering why even not overclocked I was getting erroneous crashes, I thought windows was just fucked up, I wonder is this it causing it. 

Chances are it is your Windows install that is fucked up (or something else).

The issue OP talks about is most likely very rare. It doesn't appear from just anything.

[Lord Nicoll]

Just now, LAwLz said:

Chances are it is your Windows install that is fucked up (or something else).

The issue OP talks about is most likely very rare. It doesn't appear from just anything.

Well a PC shouldn't crash while "idle", and the install is pretty healthy, only a month or two old. This CPU is usually pushed hard on 1.44v 5.2GHz, however I'm not doing much these days so it's at stock, no reason it should crash while just doing the programmes that automatically start (like discord and steam, MSI afterburner) 

[MageTank]

Just now, LAwLz said:

I didn't feel like I could add anything to your post.

Feel better now that you're quoted?

 

[Lord Nicoll]

8 minutes ago, MageTank said:

Highly unlikely, unless you are doing something very specific and niche. What are you doing while the crashes take place?

idk, I've never been at the PC, I'd notice across the room the room the blue screen, I thought it was an OC but not. For me idle just means a few programmes running in the tool bars task menu. That said automated stuff runs sometimes, but at stock on a pretty fresh OS (installed when I got this CPU) should not crash randomly, 

[Misanthrope]

59 minutes ago, Morgan MLGman said:

Well, I for instance have seen a few Digital Foundry vids when the same gen i7 and i5 were compared, i5 loses up to 35FPS in games compared to an i7 (that's with a bottleneck scenario - testing at 1080p with Titan X Maxwell as a GPU) and the frametimes jump literally all around the place on i5s.

I didn't deny that scenario though: From the get go I said that while it might be growing, I still consider it sort of a smaller scale case scenario vs the majority of gaming builds.

 

Other than that I think we mostly agree.

[MageTank]

3 minutes ago, Lord Nicoll said:

idk, I've never been at the PC, I'd notice across the room the room the blue screen, I thought it was an OC but not. For me idle just means a few programmes running in the tool bars task menu. That said automated stuff runs sometimes, but at stock on a pretty fresh OS (installed when I got this CPU) should not crash randomly, 

Are you crashing at stock clocks/voltages? Or only when running your OC? What were the blue screens? Use bluescreenview and get to the bottom of it. Don't just look at some very obscure HT related issue and automatically assign blame to it without knowing for certain.

 

If you were crashing while at 5.2ghz, then I can certainly say that's probably the cause. Yes, you can even crash at idle with unstable overclocks. In fact, degradation at high volts (I consider 1.44v to be pretty high) can cause once stable OC's to be unstable. It's also possible that it was never really stable in the first place, and it's extra unstable now. 

 

This is why I keep my mantra simple. Stable until unstable, lol. 

[Lord Nicoll]

Just now, MageTank said:

Are you crashing at stock clocks/voltages? Or only when running your OC? What were the blue screens? Use bluescreenview and get to the bottom of it. Don't just look at some very obscure HT related issue and automatically assign blame to it without knowing for certain.

 

If you were crashing while at 5.2ghz, then I can certainly say that's probably the cause. Yes, you can even crash at idle when unstable overclocks. In fact, degradation at high volts (I consider 1.44v to be pretty high) can cause once stable OC's to be unstable. It's also possible that it was never really stable in the first place, and it's extra unstable now. 

 

This is why I keep my mantra simple. Stable until unstable, lol. 

At stock too, 1.44 really isn't high, I've ran Skylake at 1.64v on chilled liquid, I'm more of an extreme guy, HWbot and all. The CPU is obviously delidded. I never got back fast enough to read the crash reason, however it could be something really mundane, it probably is, however I don't feel like disabling SMT just to find out, if it only crashes at idle after an hour or so oh well, not like it was doing anything, 

[MageTank]

Just now, Lord Nicoll said:

At stock too, 1.44 really isn't high, I've ran Skylake at 1.64v on chilled liquid, I'm more of an extreme guy, HWbot and all. The CPU is obviously delidded. I never got back fast enough to read the crash reason, however it could be something really mundane, it probably is, however I don't feel like disabling SMT just to find out, if it only crashes at idle after an hour or so oh well, not like it was doing anything, 

That's the point. You don't have to disable SMT to find out. Download bluescreenview and figure out the exact stop code. You can learn an awful lot by knowing that alone. Also, it's not the volts by themselves that worry me, it's the current being pushed through your CPU that causes the issues. Monitor your VRM power in/out and make sure it's within your VRM's specs. 

 

Also, is your memory overclocked? Even XMP overclocks can be unstable. Run memtest86 to check if timings are within tolerance of IMC, then use your preferred memory stress test (HCI, Prime95, Google's memtest, etc) to validate stability. Either way, it's almost impossible for this issue to be the problem you are having, if it's happening at stock clocks on a normal Windows Install, without you running specialized code/instruction sets in a specific order. I've owned both the 6700k and 7700k, and have not had this issue with HT always being on. While I know people hate the "well, it hasn't happened to me" argument, but in this case, I think it applies. 

[PCGuy_5960]

4 hours ago, Misanthrope said:

Minimum framerate also isn't that much worst without hyperthreading. 

Minimum FPS isn't really important. 1% and 0.1% lows are much more accurate

Spoiler

As you can see from the benchmarks, there's a noticeable improvement when going from the i5 to the i7. So an i5 isn't "all you need" for gaming anymore. This is why if you have a 6700K/7700K you shouldn't disable Hyperthreading, if you don't use programs that trigger the bug.

[Husky]

Thank you Intel!

[Lord Nicoll]

Just now, MageTank said:

That's the point. You don't have to disable SMT to find out. Download bluescreenview and figure out the exact stop code. You can learn an awful lot by knowing that alone. Also, it's not the volts by themselves that worry me, it's the current being pushed through your CPU that causes the issues. Monitor your VRM power in/out and make sure it's within your VRM's specs. 

 

Also, is your memory overclocked? Even XMP overclocks can be unstable. Run memtest86 to check if timings are within tolerance of IMC, then use your preferred memory stress test (HCI, Prime95, Google's memtest, etc) to validate stability. Either way, it's almost impossible for this issue to be the problem you are having, if it's happening at stock clocks on a normal Windows Install, without you running specialized code/instruction sets in a specific order. I've owned both the 6700k and 7700k, and have not had this issue with HT always being on. While I know people hate the "well, it hasn't happened to me" argument, but in this case, I think it applies. 

Well the board is an ROG Maximus VIII Formula, so it's definitely well within spec, the system on cinebench at 5.2GHz pulled just 200 watts from the wall, so it's not that bad. Chances are, something like that error would be very rare, however let me blame it on something easy haha, the memory is also stock, I just cleared CMOS and saved, so completely stock, including memory, I think it defaulted to normal 2133MHz CL15. Once the CPU doesn't exceed 100 amps for more than a few cycles it's fine, the current is set to 100 amps in DIGI+ control just an 10% allowed. 

[Misanthrope]

2 minutes ago, PCGuy_5960 said:

Minimum FPS isn't really important. 1% and 0.1% lows are much more accurate

  Reveal hidden contents

As you can see from the benchmarks, there's a noticeable improvement when going from the i5 to the i7. So an i5 isn't "all you need" for gaming anymore. This is why if you have a 6700K/7700K you shouldn't disable Hyperthreading, if you don't use programs that trigger the bug.

Didn't say blanket "gaming" I've been talking about specific case scenarios. Most gamers have limited budgets and the push they'd get on that limited budget is far higher and on far more games on a GPU upgrade than a CPU upgrade if you cannot upgrade both.

 

Again anything that disagrees with "This number is higher henceforth better" is ignored here, no nuance to so many of you there's no possible situation where hyperthreading isn't worth intel's asking price because look, minimums, 1% lows, that's it! Nothing else to it.

 

 

[PCGuy_5960]

1 minute ago, Misanthrope said:

Most gamers have limited budgets and the push they'd get on that limited budget is far higher and on far more games on a GPU upgrade than a CPU upgrade if you cannot upgrade both.

1. A 6600K with a Z270 board costs as much as a 7700 with a B250 motherboard
2. A Ryzen 5 1600 or 1400 are much better choices than i5s

[MageTank]

11 minutes ago, Misanthrope said:

Didn't say blanket "gaming" I've been talking about specific case scenarios. Most gamers have limited budgets and the push they'd get on that limited budget is far higher and on far more games on a GPU upgrade than a CPU upgrade if you cannot upgrade both.

 

Again anything that disagrees with "This number is higher henceforth better" is ignored here, no nuance to so many of you there's no possible situation where hyperthreading isn't worth intel's asking price because look, minimums, 1% lows, that's it! Nothing else to it.

 

 

I am sorry you feel that way. You are arguing price:performance to people that are strictly talking about performance. In fact, you only recently brought price into the equation, which saddens me further considering it was never a part of the argument in the first place. Someone mentioned HT helps with minimum framerates, which is a fact, and you keep trying to argue that HT isn't as important for gaming as people say. The only one that lacks nuance here, is you.

[Princess Luna]

I didn't understand fully what the bug is all about but I won't disable HT or else I could've just bought an i5 7600 instead lol

[Misanthrope]

13 minutes ago, PCGuy_5960 said:

1. A 6600K with a Z270 board costs as much as a 7700 with a B250 motherboard
2. A Ryzen 5 1600 or 1400 are much better choices than i5s

A 7500 on the same B250 board is cheaper and probably allows for a GPU upgrade on a close budget. Yes this present issues with 1% low on some games and definitively not an option for high refresh rate that's why I already said Ryzen is a far better choice overall (except again high refresh rate gaming which remains a very premium entry level no matter what)

 

 

[Dylanc1500]

3 minutes ago, Princess Cadence said:

I didn't understand fully what the bug is all about but I won't disable HT or else I could've just bought an i5 7600 instead lol

Basically there is a certain set of instructions that if ran in specific manner, can cause issues. However, you as a typical consumer are highly unlikely to encounter this.

[PCGuy_5960]

3 minutes ago, Misanthrope said:

A 7500 on the same B250 board is cheaper and probably allows for a GPU upgrade on a close budget.

An R5 1400 with a B350 motherboard is cheaper and better, there's literally no reason to get a brand new i5 right now......

[Misanthrope]

4 minutes ago, PCGuy_5960 said:

An R5 1400 with a B350 motherboard is cheaper and better, there's literally no reason to get a brand new i5 right now......

Well I'm glad we agree then.

[Dylanc1500]

4 minutes ago, PCGuy_5960 said:

An R5 1400 with a B350 motherboard is cheaper and better, there's literally no reason to get a brand new i5 right now......

Sure there is. Think silicon ninja stars.

[PCGuy_5960]

1 minute ago, Dylanc1500 said:

Sure there is. Think silicon ninja stars.

EVEN BETTER! YOU GET A COOL INTEL I5 STICKER!

[Dylanc1500]

1 minute ago, PCGuy_5960 said:

EVEN BETTER! YOU GET A COOL INTEL I5 STICKER!

Intel could make some money with the worlds first silicon ninja star that you can put in your computer. It's lightwieght and can be sharpened like crazy. People would flock.

[Misanthrope]

19 minutes ago, Dylanc1500 said:

Intel could make some money with the worlds first silicon ninja star that you can put in your computer. It's lightwieght and can be sharpened like crazy. People would flock.

Or you know: just flip the switch on the i5 HT and release a compeling 6 core i7.

 

But that's clearly crazy talk for them, quickly lets release an i5 on X299 instead!