Upgrading from an Intel Core i7-2600K: Testing Sandy Bridge in 2019
by Ian Cutress on May 10, 2019 10:30 AM EST- Posted in
- CPUs
- Intel
- Sandy Bridge
- Overclocking
- 7700K
- Coffee Lake
- i7-2600K
- 9700K
Power Consumption
One of the risk factors in overclocking is driving the processor beyond its ideal point of power and performance. Processors are typically manufactured with a particular sweet spot in mind: the peak efficiency of a processor will be at a particular voltage and particular frequency combination, and any deviation from that mark will result in expending extra energy (usually for better performance).
When Intel first introduced the Skylake family, this efficiency point was a key element to its product portfolio. Some CPUs would test and detect the best efficiency point on POST, making sure that when the system was idle, the least power is drawn. When the CPU is actually running code however, the system raises the frequency and voltage in order to offer performance away from that peak efficiency point. If a user pushes that frequency a lot higher, voltage needs to increase and power consumption rises.
So when overclocking a processor, either one of the newer ones or even an old processor, the user ends up expending more energy for the same workload, albeit to get the workload performed faster as well. For our power testing, we took the peak power consumption values during an all-thread version of POV-Ray, using the CPU internal metrics to record full SoC power.
The Core i7-2600K was built on Intel’s 32nm process, while the i7-7700K and i7-9700K were built on variants of Intel’s 14nm process family. These latter two, as shown in the benchmarks in this review, have considerable performance advantages due to microarchitectural, platform, and frequency improvements that the more efficient process node offers. They also have AVX2, which draw a lot of power in our power test.
In our peak power results graph, we see the Core i7-2600K at stock (3.5 GHz all-core) hitting only 88W, while the Core i7-7700K at stock (4.3 GHz all-core) at 95 W. These results are both respectable, however adding the overclock to the 2600K, to hit 4.7 GHz all-core, shows how much extra power is needed. At 116W, the 34% overclock is consuming 31% more power (for 24% more performance) when comparing to the 2600K at stock.
The Core i7-9700K, with eight full cores, goes above and beyond this, drawing 124W at stock. While Intel’s power policy didn’t change between the generations, the way it ended up being interpreted did, as explained in our article here:
Why Intel Processors Draw More Power Than Expected: TDP and Turbo Explained
You can also learn about power control on Intel’s latest CPUs in our original Skylake review:
The Intel Skylake Mobile and Desktop Launch, with Architecture Analysis
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HStewart - Friday, May 10, 2019 - link
I think one needs to look at more than just the basic benchmarks and especially multithreading.. Single thread performance has almost triple in new machines also with AVX,I think it would be nice to see what quad core cpus of Sandy Bridge and new ones do without hyperthreading. it would be nice to see the effects of hyperthreading on and off on different. benchmarks.
RSAUser - Saturday, May 11, 2019 - link
How many AVX2 workloads do you have? Adobe's suite has AVX, FF as well, past that can't think of anything that needs AVX2 support where it would be noticeable in my day-to-day stuff, pretty much nothing is interdependent in games, and even those cases where it is, it's not worth the effort of implementation for a tiny gain.AVX512 is pretty much in the ML space, wouldn't be running most of that stuff on my home machine.
HStewart - Friday, May 10, 2019 - link
"we seem to be back to Athlon vs. P4 days"This time instead of just adding frequency - they are adding cores instead of architexture on both sides currently. Maybe 2nd half will be different.
Targon - Tuesday, May 14, 2019 - link
AMD isn't sitting still, and IPC improvements from Ryzen 3rd generation are expected to be in the 13-15 percent range compared to the second generation. Clock speeds are also expected to be significantly higher, though a lot of Intel fans seem to really be pushing that AMD won't have faster than a 4.7GHz clock speed from the new generation. That IPC improvement is all about architecture improvements, clock speed is from the fab process jump.IVIauricius - Friday, May 10, 2019 - link
I've got mine paired with an RX Vega 56 in a Hackintosh. Still gets it done when compiling games for iOS. I had to move to more cores on my main PC, though. Thank you Amazon for that $250 1920X when Threadripper 2 dropped last year! :)BunnyRabbit - Friday, May 10, 2019 - link
Keeping my 3770 until probably next year when there is ddr5 + PCI Express 4.0/5 + usb 4 support.znd125 - Friday, May 10, 2019 - link
Great article. Conclusions are clear and fair.Khenglish - Friday, May 10, 2019 - link
I'm using a 3920xm at 4.4ghz, which is the mobile equivalent of the 3770K. This review just reaffirms that for 4K there is no benefit to something new.With how much the 9700K leads the 7700K at lower resolutions though this makes me think that old quads without HT are really suffering now. I am curious how the 2500K and 3570K are fairing. Probably not well.
poohbear - Friday, May 10, 2019 - link
I upgraded from a 2500k (also a legend!) to a 4790k, it was an ok upgrade, and i said next time im gonna upgrade only when its 8 cores. So, i guess that time has come, but im waiting for 10nm. So...from what im reading about 10nm for desktops ill be waiting until 2021....utmode - Friday, May 10, 2019 - link
why not AMD 7nm? unless you are in tribalism.