Features - QOTW: Do you favour efficiency or performance in your CPU?

[Rad77]

[QUOTE=Rad77;996945]

... both overclock/overvolt under load while underclocking/unclocking ...
oops - meant to type " underclocking/undervolting" of course.

[devBunny]

I'll take all the performance that I can get for the price and if the system is efficient then that's great. On the other hand, although I can get more by overclocking, as it's 24/7 number crunching, I won't overclock too far up the exponential power curve as I don't want to kill the beast or the budget. So it's: price, performance, efficiency.

[keithwalton]

Power and efficiency is what team blue have been championing for some time now and the mobile haswell chips are a case of you can have your cake and eat it too.

I have an i7-4800mq, low use web browsing and listening to youtube etc it clocks down to 800mhz and 0.686v and uses all of 2.5W
watch a video and it cranks up to 10w (passive cooling at these speeds)

It's native clockspeed is 2.7GHz and it needs 30w to hit this speed, it has turbo boost which cranks the clockspeed upto a max of 3.5GHz on 4 cores or 3.7ghz on 1 core.

And thanks to intel's extreme tuning utility it also has an overboost function which for a limited time will increase the max tdp allowed which means I can run at 3.9Ghz on 4 cores for 30 seconds.

I have also tuned it such that it will run at 4.1GHz indefinitely if only one core is needed.

I also have some hardware from team green (780m) which uses almost no power unless it's required by a game. It's in completely different league to the apu's in that it has a TDP of 100w but it achieves 120fps in f1 2013 on ultra settings (4x the fps of the fastest kaveri) but if i tell it I only want 60fps (vsync) it cranks down the power required to match.

[Scow Captain]

I'd run the A8-7600 at 45W for use as a HTPC but 65W for anything else. It's nice users have the choice and flexibility to change wattage in the bios with this chip. You could buy the A8 and use it for a bunch of tasks through its life. Example, if you have young kids not ready to use their own computer yet, use it for a HTPC then up the wattage so the kids can play Minecraft when they're old enough.

[loki365]

Difficult to say. I'm not exactly frakking n00bs over here, most of my gaming effort these days is expended exploring Azeroth and Faerun but I'm open to Warframing, especially when the patches catch up and I can play with my PS4 owning mates.

I'd probably say efficiency right now as I'm playing fairly sedate games and the cooling I use is to promote my hardware's longevity.

[scaryjim]

The problem with efficiency in terms of computers is that there are two sides to making a computer efficient, depending on what you do with it.

For some tasks, the computation side is the bottleneck and here you need to look at total task energy (as hinted at by peterb earier) - if a 50W chip takes 4x as long to complete the task as a 100W chip, then it's only half as efficient (it'll use twice as much total energy competing the task). So that's where you have to balance power draw with computational capacity - the A8 actually does very well on this score (in 45W mode) as the % performance drop is somewhat less than the % power reduction.

However, for a lot of uses the computation side isn't the deciding factor - if you watch a DVD or play a game, the speed/power available to your computer won't allow you to finish watching or playing in less time. At that point you need to decide what level of performance is adequate for your needs - for gaming, for instance, you may get a more enjoyable experience from higher power components (at the cost of higher power draw and total energy consumption).

Of course pretty much ALL processors will reduce their power consumption when they're not running at full whack - which is why idle power draw figures in reviews are much lower than load power draws. What AMD are doing with the A8 7600 is allowing consumers to cap the peak amount of power the chip will draw, which is a very different thing. It's a feature that's been implemented in server chips for a while now (where saving a few watts per processor can actually make a huge difference to the power consumption of a data centre), although I'm not sure how relevant it is to consumer products - it almost begs the question of why stop at 45W/65W - AMD could essentially do away with grades within performance bands and have TDP configurable A10, A8 and A6 processors where each TDP configuration gives different clock speeds and the consumer chooses between 95W, 65W, 45W, perhaps even 35W based on their usage. After all, it's what some enthusiasts have been doing for years with underclocking and undervolting, just with a better defined set of values...

[zdn1042]

A little of both would be nice. I would go with Performace: 60%, Efficieny: 40%.

[zzzaac]

Depends, for laptops, I favour efficiency. For PC's, performance.

[ET3D]

I lean toward efficiency, but within reason. If I can save 30% power and only have a 10% performance drop, that seems worthwhile to me.

One thing I often comment about is my wish to see undervolting results in reviews. CPU's and GPU's can often run well undervolted, and this saves power while providing the same performance, yet for some reason this is never tested.

[NiPPonD3nZ0]

as Jeremy Clarkson usually says, the solution is allways PPPOOOOOOWWWWAAAAAAAA

[Holythief]

I generally prefer performance over efficiency

[Torashin]

Performance; my house is always freezing so any "inefficient" heat production is welcome!

[anselhelm]

I don't see why this should be an "either/or" question when Intel has proven you can have both with its offerings over the last few years.

Now, don't get me wrong: I'm neither an AMD-hater nor an Intel-zealot. What I am is someone who's been using AMD processors for years as they've been better performance and value for money, but recently I've lost most faith in AMD's ability to make CPUs.

AMD has completely conceded the high-end of the market to Intel and as such has allowed Intel to continue to price its products far higher than it would have otherwise. What AMD has done well, though, is push its low- to mid-end APUs and continue to develop these, especially in terms of reducing their power requirements.

Kaveri will probably make a great laptop chip and I am looking forward to potentially seeing mid-end gaming laptops with such APUs inside to create gaming laptops under £500. But without any progress on the high-end, it's hard to find AMD's general chips appealing, especially when you take Intel's chips into account.

Sure, you pay more up-front for an Intel setup, but you then have a quieter, cooler and less power-hungry rig that saves you in the long-term. The power usage of AMD's ageing Vishera FX chips is just one reason that I could never now recommend one to anyone I know in good faith.

At least AMD is doing well on the graphics front and I hope that it continues to at least push this part of its business with the same passion that it's been doing, especially in terms of improving its graphics drivers with regards to micro-stutter and other issues it's had for years. (Again, I'm not an AMD-hater here, as I've an unlocked HD 6950 in my system right now.)

Perhaps I'm just jaded by the slow progress AMD has made, but I now find myself in the position where I'd only recommend AMD for a low to mid-end system (or a laptop) with a low power budget. For anything else, I'd recommend someone to wait for the Haswell refresh and Z97/H97 chipsets (if possible) in order to ensure a future upgrade option for Broadwell processors. I'd only recommend highest-end enthusiasts to wait for Skylake in 2015.

On that note, it's amusing how much I used to berate Intel for its changing of motherboards with every tick-tock when AMD's socket AM3+ is effectively dead and FM2+ is only guaranteed to get one more processor after Kaveri in the form of the Excavator-core Carrizo.

Anyways, I've said about as much as I need to here, I think.

[ET3D]

AMD has completely conceded the high-end of the market to Intel and as such has allowed Intel to continue to price its products far higher than it would have otherwise.

While I generally agree with you (though I think the main reason Intel wins is its production capability), I just wanted to correct you on this point. Lack of competition slows down innovation, it doesn't raise prices. Quite the opposite is true. It was AMD's competition years ago that raised prices in the first place, going from ~$300 to ~$1000 by introducing enthusiast processors. We're now back to where most people's notion of a high end CPU is a ~$300 CPU (although higher end does exit). If AMD ever went back to being competitive, it's possible we'll see another battle with rising prices. However, it will be coupled with a large performance increase, which will make it worthwhile for enthusiasts.

[Top_gun]

I will choose my next processor on how little it would draw on power. Why waste the planet or make fat cats at energy companies even richer?

These days, most CPUs are plenty for most people unless you're a gamer or do heavy graphics processing work.

[T Muffy]

Performance. If I want to cut my expenses I can do so in ways that won't take quality away from any thing.