With the new Sandy Bridge CPUs, you can change the clock multiplier as well as the turbo boost multipliers. It's unclear to me what happens if you set the base multiplier higher than any of the turbo boost multipliers.

Say you have a 2600K and you set the main multiplier to 40, but leave the turbo boost multipliers unchanged. Will the CPU underclock itself if it tries to kick in Turbo Boost, or will it only activate Turbo Boost for the multipliers set higher than the base?

The overclocking guides I've looked up via google are unclear on this. I found many guides that either ignore the Turbo Boost issues or deactivate it. The guide from Gigabyte ignores the base multiplier and just alters the Turbo Boost multipliers.

I'm not looking for an agressive overclock or anything. I'm just looking for clarification on the relationship between the base multiplier and the Turbo Boost multipliers as I experiment with overclocking.

6/13/2011 2:38:27 PM

while it's cool to play with for a week or 2, it's a complete waste of time given how cheap hardware is and how much software lags behind hardware (in most cases). I'd just assume run it stock or buy nicer to start with if that's not good enough.

6/13/2011 3:32:07 PM

if you're overclocking up to or over the turboboost levels why not just disable it - you're getting no benefit from it anymore.

6/13/2011 3:33:49 PM

^^A valid point, but irrelevant to this discussion. I'm trying to suss out the technical details behind my poorly documented motherboard manual.

^Does that imply that the turbo boost multipliers should be set to higher values to scale along with the base multiplier value? e.g. base: 40; T4: 41; T3: 42, T2: 43: T1: 44

6/13/2011 4:08:34 PM

No, you just make them all the same.

Base, T4, T3, T2, T1 should all be the same if you are going to overclock beyond the stock settings.

For instance, the base clock is 100Mhz.

Base multiplier is 33 = 3.3 Ghz stock
T4 is 34 = 3.4
T3 is 35 = 3.5
T2 is 36 = 3.6
T1 is 37 = 3.7

If you want to go straight to 4.0Ghz, just set all of the multipliers to 40. Done. No turbo needed.

So to be really basic about what "Turbo" means is that it's the speed of one core when not all cores are being utilized. Because you're overclocking for FULL system performance, you need to know what the highest speed can be reached with ALL four cores are FIRST, before OC'ing a single core. So hit the highest speed first, then see if you can up the individual cores after that. But it's pointless to scale the T1-T3 turbo speeds until you find the T4 max OC is.

[Edited on June 13, 2011 at 5:38 PM. Reason : .]

6/13/2011 5:32:14 PM

Quote :

"while it's cool to play with for a week or 2, it's a complete waste of time given how cheap hardware is and how much software lags behind hardware (in most cases). I'd just assume run it stock or buy nicer to start with if that's not good enough."

I don't think this is a valid point at all. You can't buy a stock 4.0ghz cpu or faster unless you buy it factory overclocked by someone like Dell/Alienware. You might as well do it yourself. The extra processing power gives you a multitude of advantages in a variety of software not just gaming.

Quote :

"hardware is and how much software lags behind hardware (in most cases)"

This doesn't exactly make sense. If you're dealing with rendering, encoding, running large filters, vlookups, etc, anything that takes lots of processing power you're always limited by the CPU's frequency. The higher you get it the faster your stuff processes. I don't see how getting a nice 4.5ghz overclock on one of the new Sandy Bridges (which is really easy I hear) is "a waste of time" if it greatly improves your processing power.

6/15/2011 1:30:35 PM

I don't really understand the rationale of not getting maximum performance from your sandybridge when you can.

6/15/2011 2:38:02 PM

^ ^^ the things you mention are largely parallel, and benefit more from scaling horizontally (read more cores) than increasing mips on a single core. i just fail to see the point in reducing the life span of a cpu for it to accel in a select few use cases instead of just buying a faster processor. if you're cpu capped often enough for it to be an inconvenience and can't buy a faster processor, send the work to a grid/cloud.

[Edited on June 15, 2011 at 2:46 PM. Reason : board and memory lifespan as well]

6/15/2011 2:45:10 PM

That doesn't make any sense. You're getting 4-8 threads with these processors for cheap. You can overclock them to 4-4.5ghz easy. There's no "faster processor" out there. Sure I can upgrade to a server motherboard and get a couple 6 core Gulftown/Xeons but they're $$$ and the performance/cost ratio is tiny and you won't be getting any speed increase. You're much better throwing an after market cooler on a cheaper processor and FOR FREE getting great performance out of it.

And decreasing the life of my CPU? I assume that's a joke. With modern throttling technology and running it 24/7 at 100% utilization I'm going to want to upgrade way before it dies years down the road. These processors run cooooool. They're not going to damage the motherboards or ram. Low latency high speed ram is so cheap now it's RATED to be overclocked.

I just don't see how spending $1000's on more cores is worth it when there's a free option out there. Intel even praises how great Sandybridge is at overclocking. You're SUPPOSED to do it. If this were 10 years ago you might have a point but right now the performance increase you get from overclocking for practically no money far outweighs any other options.

-I need to reemphasize the point. There's NO FASTER Processor you can buy. Sandy Bridge has unlocked multipliers. There's no point buying a higher clocked one. They don't sell them. The i7 2600k has an unlocked multiplier and goes to 3.8ghz STOCK. You might as well overclock it to 4.5 or beyond. It's free and they practically tell you to.

[Edited on June 15, 2011 at 3:06 PM. Reason : s]

6/15/2011 3:03:03 PM

these are consumer level chips. they have much lower tolerances than server chips. if they were reliable at the same service lengths at higher multipliers, that's the multiplier it would have shipped with. intel doesn't just bin for the hell of it. also, what about the life of the motherboard? there's nothing free about overclocking. you're shortening the life of your equipment for up front speed gains that are largely unnecessary. if you want more threads, get an amd hex core for $less and unmask the extra cores for "$free"

6/15/2011 5:02:11 PM

Quote :

"if you want more threads, get an amd hex core for $less and unmask the extra cores for "$free""

I don't necessarily want more cores. There's only a few select programs that benefit from it. I have 4 cores/8 threads and that's plenty. Most applications benefit more from an increase in speed. Things process faster, games are faster, start up times are faster. I can easily notice a bump in performance going up say 500-1000mhz.

Quote :

"also, what about the life of the motherboard? there's nothing free about overclocking. you're shortening the life of your equipment for up front speed gains that are largely unnecessary. "

I think you're looking at the whole lifespan thing using the wrong approach. Overclocking doesn't necessarily shorten the life of anything. The biggest contributor that shortens the life span of any computer component is heat. The whole point of buying more efficient coolers and better motherboards is to increase heat dispersion so your components stay cooler.

If you look at a workstation Dell or IBM they typically have stock coolers and little ventilation. Half the time the CPUs idle at 50+ and get to 70+ under load. You can open up the case and the NB will be so hot it could fry an egg.

Now compare that to a high quality motherboard with multiple heatsinks and heatpipes with an aftermarket cooler on the cpu. You can crank it past 4.0ghz and it'll still idle under 40 and barely get above 50 for load.

How is it shortening the life of my equipment when everything I have runs cooler than something I would buy from a store?

[Edited on June 15, 2011 at 5:52 PM. Reason : f]

6/15/2011 5:48:50 PM

just because you more efficiently exchange the heat with the ambient air doesn't mean it was never made.

6/15/2011 7:49:10 PM

I just move my clock an hour forward. I don't see why being on a sandy bridge would enhance this.

6/15/2011 8:31:47 PM

Quote :

"And decreasing the life of my CPU? I assume that's a joke. With modern throttling technology and running it 24/7 at 100% utilization I'm going to want to upgrade way before it dies years down the road. These processors run cooooool."

sadly this is only true if you're running stock frequencies.... typically if you overclocked correctly heat is the limiting factor in which you are decreasing the lifespan of your CPU, even if you overclock 100Mhz, you are decreasing the lifespan of your CPU comparatively to what came stock.

while they do run cool, i'll agree with you on this, a Core i5-2500K can hit 4.0Ghz on stock voltage with the stock cooler without blinking and can easily hit 4.5-4.8Ghz. there is no better valued CPU, NOT EVEN CLOSE!

6/15/2011 10:44:42 PM