Sandy Bridge Turbo Algorithm & Its Affect On Games and FPS

[arh2o]

How does Sandy Bridge's turbo affect games? I've heard of instances in games (WoW) where the EIST kicks in and clock speeds range from 1.6ghz->3.3ghz->3.9ghz and fluctuate wildly between these speeds. Consequently FPS drops with these fluctuations. I've read that Sandy Bridge can turbo for anywhere between 15-25 seconds. Does anyone know additional information on the algorithms? Is there such thing as an infinitely sustainable turbo? How long is the wait between each turbo boost?

For instance I own a 2500k on a ASRock P67 Pro3 mobo. If I'm running a game, I assume the CPU will turbo up. My FPS should therefore boost from the additional clock speed but then rapidly drop after 25 seconds. Wouldn't this rapid change in clock speed affect the stability of FPS? I can see this being a problem in certain competitive online shooters where FPS stability is a must. If I'm about to shoot someone in the head and my turbo stops and my FPS drops from 40 to 25, I'm sure I would notice it. In addition, when does Sandy Bridge determine when to power down? In some older games, if there's only a little load, will the CPU actually underclock to 1.6ghz and affect FPS?

 

[IntelUser2000]

You should see at least the base clock in games. For desktop 95W quad core chips the guaranteed Turbo clock is 100MHz above the base clock.

 

[Concillian]

How does Sandy Bridge's turbo affect games? I've heard of instances in games (WoW) where the EIST kicks in and clock speeds range from 1.6ghz->3.3ghz->3.9ghz and fluctuate wildly between these speeds.

??? if EIST kicks in, then the CPU was not under high enough load to need max multiplier. This won't happen in a case where you are at high utilization.

The turbo is modulated based on thermal performance. If you can maintain a low temp, it will keep the turbo at a constant level.

Aside from that, your First person shooter FPS dropping from 40 to 25 as a result of CPU scenario just does not happen. FPS games are not so CPU dependent that the 400 MHz difference from SB turbo will cause things to run almost half speed.

There are very, very few games out right now that are going to see lower than 40 FPS due to the CPU with a SB quad, even fewer where the games are first person shooters.

 

[arh2o]

Aside from that, your First person shooter FPS dropping from 40 to 25 as a result of CPU scenario just does not happen. FPS games are not so CPU dependent that the 400 MHz difference from SB turbo will cause things to run almost half speed.

The thing is that I'm overclocking the Turbo on my system. So I'm actually going from a base frequency of 3.3ghz all the way to 4.4 ghz when Turbo kicks in. That's a 1.1ghz difference that I gain and lose in approximately 25 seconds. There has to be some odd FPS fluctuations from that.

 

[996GT2]

The thing is that I'm overclocking the Turbo on my system. So I'm actually going from a base frequency of 3.3ghz all the way to 4.4 ghz when Turbo kicks in. That's a 1.1ghz difference that I gain and lose in approximately 25 seconds. There has to be some odd FPS fluctuations from that.

If you overclock then there is no 25 second restriction. Mine runs all night @ 4.4 when I tested with Prime95

 

[Concillian]

The thing is that I'm overclocking the Turbo on my system. So I'm actually going from a base frequency of 3.3ghz all the way to 4.4 ghz when Turbo kicks in. That's a 1.1ghz difference that I gain and lose in approximately 25 seconds. There has to be some odd FPS fluctuations from that.

Again, I will state that there are very few games that will run below 40 FPS at the stock frequency because of the CPU. If it runs 40 FPS at stock frequency, it will run 40+ overclocked, which means you won't be in a situation where the turbo puts you there.

Even though it's already be stated that if you OC, turbo won't really affect you, since it's running that all the time, I still want to fully explain the point I'm trying to make.

Most of the gamers in this forum aren't seeing CPU limitations at the graphical settings they play at. It's been a while since I played FPS games, but the last time I did, I was having to underclock quite a bit before I even noticed any FPS drops. My averages and maximums dropped on benchmark programs, but my minimums (which is what I would actually notice) didn't budge until I had underclocked to like 60% of stock speeds.

SB quads are pretty powerful at stock speeds, and we are in an age of console ports that are easy on hardware. An SB at 3.3 GHz is not a severe limitation. I'd be surprised if overclocking it to 4.4 Ghz is actually giving you any benefit you would notice yourself (i.e. without a benchmarking program).

What FPS are you getting at 3.3 GHz in the games you play?

I didn't even notice anything when I was testing my own perception until minimums were in the 35 FPS range, which took rather a lot of CPU underclocking. Most people run at graphics settings which put them in a GPU limited condition. I know I was definitely GPU limited.

I always encourage people to test for themselves at stock, underclocked and overclocked and actually play in all three states at the graphics settings they normally run. Then be honest with themselves if they notice any differences. You'd be surprised how little difference the CPU makes in actual gameplay for most games. It's a lot less than I would have thought by reading CPU reviews and looking at the numbers in those reviews.

 

[taltamir]

at the base speed of sandy bridge it is still the fastest CPU on the planet, only thing faster is an overclocked/tubro sandy bridge... there is no game that will drop under 60FPS with sandy bridge base clock aside from maybe crysis.

plus what other people said about why it is totally implausible.

EIST is power saving not "lack of turbo". if you drop down to 1.6Ghz its because the CPU has absolutely nothing to do, its so under utilized. FPS will not drop in such a case.

 

[Axon]

How does Sandy Bridge's turbo affect games? I've heard of instances in games (WoW) where the EIST kicks in and clock speeds range from 1.6ghz->3.3ghz->3.9ghz and fluctuate wildly between these speeds. Consequently FPS drops with these fluctuations. I've read that Sandy Bridge can turbo for anywhere between 15-25 seconds. Does anyone know additional information on the algorithms? Is there such thing as an infinitely sustainable turbo? How long is the wait between each turbo boost?

For instance I own a 2500k on a ASRock P67 Pro3 mobo. If I'm running a game, I assume the CPU will turbo up. My FPS should therefore boost from the additional clock speed but then rapidly drop after 25 seconds. Wouldn't this rapid change in clock speed affect the stability of FPS? I can see this being a problem in certain competitive online shooters where FPS stability is a must. If I'm about to shoot someone in the head and my turbo stops and my FPS drops from 40 to 25, I'm sure I would notice it. In addition, when does Sandy Bridge determine when to power down? In some older games, if there's only a little load, will the CPU actually underclock to 1.6ghz and affect FPS?

I've experienced this. I can't say I commonly notice the FPS drop in SC2, for example, because it's usually over 90 or more. However, when an opponent brings in his army, my system pauses for a split second, obviously kicking in the turbo. Just like you said, it happens only at critical moments (e.g., only when 30+ units are about to engage my 30+ units)...and I can't stand it. It's not every time, but it is enough. If you play SC2, you know how and when you engage is critical. Anyway, I disabled all the turbo mode features and I just keep it overclocked. I'm not sure how GB does that, but I disable a number of settings in the BIOS to do this.

 

[podspi]

I've experienced this. I can't say I commonly notice the FPS drop in SC2, for example, because it's usually over 90 or more. However, when an opponent brings in his army, my system pauses for a split second, obviously kicking in the turbo. Just like you said, it happens only at critical moments (e.g., only when 30+ units are about to engage my 30+ units)...and I can't stand it. It's not every time, but it is enough. If you play SC2, you know how and when you engage is critical. Anyway, I disabled all the turbo mode features and I just keep it overclocked. I'm not sure how GB does that, but I disable a number of settings in the BIOS to do this.

IS that local play or over Bnet? Could be possible that its network latency not the CPU :twisted:

 

[Axon]

IS that local play or over Bnet? Could be possible that its network latency not the CPU :twisted:

Indeed, I've considered that. When it happens, my fans spin up, and it's always when there are a large amount of units moving on screen. I also see the same phenomenon in WoW, though it rarely matters because it only happens in crowded cities. But if I can't seige my tanks when I random Terran, I could just get my ass whipped.

 

[exar333]

I've experienced this. I can't say I commonly notice the FPS drop in SC2, for example, because it's usually over 90 or more. However, when an opponent brings in his army, my system pauses for a split second, obviously kicking in the turbo. Just like you said, it happens only at critical moments (e.g., only when 30+ units are about to engage my 30+ units)...and I can't stand it. It's not every time, but it is enough. If you play SC2, you know how and when you engage is critical. Anyway, I disabled all the turbo mode features and I just keep it overclocked. I'm not sure how GB does that, but I disable a number of settings in the BIOS to do this.

Unlikely. The CPU switches frequencies at a much higher rate than would be visible while playing a game. The 'pause' you see is the cpu processing all the new information. This would happen with or without the turbo. Locking-in a higher permenant freq (aka OCing) would mitigate this but unlikely eliminate it altogether.

 

[betasub]

The 'pause' you see is the cpu processing all the new information. This would happen with or without the turbo.

This. Switching between states is far faster than any noticable pause.

 

[Axon]

Unlikely. The CPU switches frequencies at a much higher rate than would be visible while playing a game. The 'pause' you see is the cpu processing all the new information. This would happen with or without the turbo. Locking-in a higher permenant freq (aka OCing) would mitigate this but unlikely eliminate it altogether.

I never had this issue on the X58 platform, so I really don't know what else it could be. Oh, and games are not the only scenario where I see this - even simple things, like CPUZ, hang once in a while when the frequency is ramping up. I'll move the CPUZ window, for example - pause, pause - then it bumps to whatever the turbo frequency is.

It could well be that I have a hardware issue somewhere else in the system. I suspect the motherboard could be a culprit. Unfortunately I haven't been able to change it out yet as B3 boards are only coming in now.

 

[arh2o]

Anyway, I disabled all the turbo mode features and I just keep it overclocked. I'm not sure how GB does that, but I disable a number of settings in the BIOS to do this.

And do you still experience this pause/fps drop with turbo/speedstep disabled? You should test it by enable/disable and see if there's a pattern.

 

[exar333]

I never had this issue on the X58 platform, so I really don't know what else it could be. Oh, and games are not the only scenario where I see this - even simple things, like CPUZ, hang once in a while when the frequency is ramping up. I'll move the CPUZ window, for example - pause, pause - then it bumps to whatever the turbo frequency is.

It could well be that I have a hardware issue somewhere else in the system. I suspect the motherboard could be a culprit. Unfortunately I haven't been able to change it out yet as B3 boards are only coming in now.

Yeah, it sounds like something is not working correctly. Could be a MB issue, definitely. The only CPU change that really should affect what you can measurably see would be going from a low-power state to an active state. Otherwise, turbo changes would be, for most intents and purposes, instantaneous.

 

[taltamir]

disabling the turbo (maintaining base clock speeds) would make things worse, not better. If you disable the turbo then OC the heck out of it, then it is the OC that helps not the disabling of the turbo. Switching is so fast that it would not give you a noticeable pause. Having to suddenly contend with 30+ units at once will... and actually I would say the HDD or network is more likely a culprit.