CPU turbo in a tablet?

NTMBK

Lifer
Nov 14, 2011
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Does anyone have any experience with Turbo in a tablet CPU, or has anyone read any articles examining the subject? Does the feature make any difference to the tablet in real world usage? (I'm talking about typical bursty usage when browsing the net etc, not sustained benchmark workloads where obviously there is no TDP headroom for a frequency boost.)

I'm weighing up whether it is worth getting the i5 version of a Windows 8.1 tablet instead of the i3 version. The price difference is £100, which is quite a lot, but I don't want to fork out for a tablet which turns out to be too slow and needs replacing.

The two processors in question are the i3 4020Y and the i5-4300Y. They have a tiny 100MHz clock speed difference in the base clock, but the i3 does not have turbo boost enabled- whereas the i5 can boost up to 2.3GHz, an almost 50% clock speed increase!

But will I ever actually see the effect of this in the real world? Does a fanless tablet have enough thermal headroom to let it hit 2.3GHz, or will it never get anywhere close to that? And even if it does, is the difference in performance enough to make a noticeable difference?
 

Ventanni

Golden Member
Jul 25, 2011
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I can't imagine you wouldn't with something like a heavy webpage load. Anything on a Windows tablet is probably going to feel pretty snappy, but what's the price difference?

Edit - I kan reed.

I'd say go for it. For 100 pounds, definitely worth it.
 

monstercameron

Diamond Member
Feb 12, 2013
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I dont believe it will make much difference between and i3-i5 if you are doing things like browsing. I'd save the $100.
 

NTMBK

Lifer
Nov 14, 2011
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I dont believe it will make much difference between and i3-i5 if you are doing things like browsing. I'd save the $100.

I just picked browsing as it tends to like single threaded performance and people run benchmarks on it, to be honest- I intend to use it as a general purpose laptop, as well as just a "noodling on the internet while watching TV" device. Expect video watching, light gaming, etc, as well as just internet browsing.
 

monstercameron

Diamond Member
Feb 12, 2013
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I just picked browsing as it tends to like single threaded performance and people run benchmarks on it, to be honest- I intend to use it as a general purpose laptop, as well as just a "noodling on the internet while watching TV" device. Expect video watching, light gaming, etc, as well as just internet browsing.

then its a no-brainer, more perf for $100 would go along way and haswell is pretty good in idle situations so battery life when not taxing it should be near identical to the i3 sku
 

Techhog

Platinum Member
Sep 11, 2013
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I don't see it hitting full boost without a fan. In fact, if you want light gaming, get an ultrabook instead. Fanless Haswell just sounds like throttle city.
 

NTMBK

Lifer
Nov 14, 2011
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I don't see it hitting full boost without a fan. In fact, if you want light gaming, get an ultrabook instead. Fanless Haswell just sounds like throttle city.

When I say "light gaming", I mean light. I'm talking point and click games off GoG.com and a bit of pinball, not Battlefield 4. ;) I don't expect it to hit high turbo speeds for prolonged periods, but I would hope that it would kick in enough to make a difference in "peaky" workloads. As far as I can tell, Turbo is designed precisely for thermally constrained situations- so that the GPU and CPU cores can clock up and down to get as much performance as possible in a given thermal window.

Has anyone seen any definitive writeups on how turbo behaves in such a thermally constrained environment? Anand wrote this about the Surface Pro 2:

Internally we see where Microsoft spent most of its time updating Surface Pro. It all starts with an upgrade to Haswell. Surface Pro 2 features Intel’s Core i5-4200U, a dual-core 1.6GHz 15W Haswell part with Hyper Threading, 3MB of shared L3 cache, and a max turbo frequency of 2.6GHz. Just like last time, I had no issues hitting 2.6GHz on Surface Pro 2. I would see 2.3GHz far more frequently however.

However, the SP2 uses a slightly higher TDP part (15W vs 11.5W), and has a fan in it.

Note: I can't 100% guarantee that this is a fanless tablet, so I could be wrong. There are two versions of this tablet, the Venue 11 Pro, one with Bay Trail and one with Haswell- it seems like everybody who reviewed it took a look at the Bay Trail model, annoyingly! The Haswell one is a little thicker, and I don't know if that's because of the larger battery or because they snuck a little fan in there somewhere.

EDIT: Okay, finally managed to track down a video where someone goes in depth with the Haswell model, and it does have a fan in it (unlike the Bay Trail version of the same tablet).
 
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NTMBK

Lifer
Nov 14, 2011
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Bit the bullet and ordered the Venue 11 Pro, maxed out with i5-4300Y, 8GB RAM and 256GB SSD. Looking forward to trying out ultramobile Haswell!
 

Homeles

Platinum Member
Dec 9, 2011
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I think you made the right choice. Mobile i3s have always seemed lackluster to me. Turbo is such a critical feature these days -- look at how poorly Kabini fares. It should be a feature enabled on every part, from top to bottom.
 

NTMBK

Lifer
Nov 14, 2011
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I think you made the right choice. Mobile i3s have always seemed lackluster to me. Turbo is such a critical feature these days -- look at how poorly Kabini fares. It should be a feature enabled on every part, from top to bottom.

Yeah, balancing a power budget to make the most of a limited TDP seems like such an essential feature in a tablet part.

(And hopefully Beema/Mullins finally sorted out CPU turbo- I agree that its absence in Temash was a disaster!)