Core Voltage
A measured average voltage of 1.319 V (with the UEFI set to just 1.195 V) shows that you can’t hold back if you want to push Haswell-E a gigahertz beyond its default peak frequency. Expect some extreme power consumption and temperature numbers.

Power Draw
The following graph shows the contrast between what we read from the voltage regulator and EPS connector, making it easy to calculate losses in the process.

At idle, power use is minimal. A 19 W result is ever-so-slightly higher than our reading at 4 GHz. But a 70 W jump under load for an additional 500 MHz tells us we can't expect much more from the Core i7-5960X on water cooling, particularly since the VR-based losses have doubled.
| Power Consumption | Average Idle | Maximum, 100% Load | Average, 100% Load |
|---|---|---|---|
| CPU 12 V In | 24 W | 280 W | 240 W |
| CPU Package | 19 W | 195 W | 192 W |
| VRM Loss | 5 W | 85 W | 48 W |
Temperatures
The temperatures at idle are still nice and low. However, those big fluctuations under load are clear indications that power delivery is becoming more erratic, and throttling is starting to become an issue. For brief periods, our Core i7-5960X cannot sustain 4.5 GHz. It jumps between 4.3 and 4.5 GHz, rather than sacrificing stability.

Here’s the time-lapse video:
| Temperature T | Idle | Maximum, 100% Load | Average, 100% Load (Heated Up) |
|---|---|---|---|
| Core | 27 °C | 87 °C | 75 °C |
| Package | 29 °C | 66 °C | |
| Water (In / Out) | 24 °C / 28 °C | 38 °C | |
| VRM | 34 °C | 67 °C |
Six Cores At 4.5 GHz
Core Voltage
Does cutting a couple of cores from the equation help bring power back under control? An average core voltage of 1.319 V is just as aggressive, surprisingly enough. Try dialing in something more conservative in the BIOS, though, and you lose stability with this particular sample.

Power Draw

At idle, there's not much difference from the six-core and 4 GHz setting. But a 50 W jump under load (60 W with losses added in) is almost as bad as what we saw from eight cores. You'll have to decide if that's worthwhile for an extra 500 MHz.
| Power Consumption | Average, Idle | Maximum, 100% Load | Average, 100% Load |
|---|---|---|---|
| CPU 12 V In | 21 W | 214 W | 175 W |
| CPU Package | 17 W | 154 W | 150 W |
| VRM Loss | 4 W | 60 W | 25 W |
Temperatures
Switching off two cores frees up enough thermal headroom to drop maximum temperatures under load by quite a bit. But that doesn't mean you can get away with a cheap air cooler, either. Liquid cooling is the way to go for its ability to quickly draw heat away from the spreader and exhaust that energy out of your chassis by blowing through a big radiator.

| Temperature T | Idle | Maximum, 100% Load | Average, 100% Load (Heated Up) |
|---|---|---|---|
| Core | 27 °C | 82 °C | 68 °C |
| Package | 29 °C | 55 °C | |
| Water (In / Out) | 24 °C / 28 °C | 36 °C | |
| VRM | 34 °C | 54 °C |
Quick escalation in our power consumption measurements push cooling into the spotlight. We're able to keep a six-core processor running well, but eight cores is pushing it. In spite of the relatively low water temperature, Intel's Core i7-5960X gets so hot that it starts throttling.
- Three New CPUs For Enthusiasts
- X99, LGA 2011-3 and DDR4: Get Ready For A Big Upgrade
- How We Tested Core i7-5960X, -5930K, And -5820K
- Synthetic Benchmarks
- Real-World Benchmarks
- Battlefield 4, Grid 2, And Metro: Last Light
- Star Swarm, Thief, Tomb Raider, And WoW
- Power, In Depth: Stock Clock Rates
- Power, In Depth: Eight and Six Cores at 3.5 GHz
- Power, In Depth: Eight and Six Cores at 4 GHz
- Power, In Depth: Eight and Six Cores at 4.5 GHz
- Power, In Depth: CPU Health at 4.8 GHz
- Measuring DDR4 Power Consumption
- Power Consumption Through Our Benchmark Suite
- Intel Keeps Enthusiasts On Its Most Modern Design With Haswell-E

Personally, the 3DS and After Effects benchmarks were of most interest, since they are what I spend most of the CPU time on. (3DS in particular, right now I'm logging dozens of CPU hours a day on 3DS alone). It's pretty clear that unless the platform costs of Haswell-E are much higher than IB-E, going with the old won't make sense. The 5930k beats the 4960X. which is at least 50% more expensive.
I've been waiting forever for an upgrade to my i7 930 based workstation, and I didn't feel like jumping on an IB-E a couple months before a brand-new HEDT platform is released.
I had hoped Haswell-E would be a bit more impressive, but OTOH, investing in a DDR4 platform now might be a good idea, given my workstations typically have 3-4 years in them. At the very least, a drop-in upgrade to Broadwell-E would be nice to have as an option.
Now to see how big a pounding I'll take in Denmark for X99/DDR4/Haswell-E...
Therefore anybody who's going to load up on GPUs enough to worry about PCI-E lanes will have sufficient money to drop in a 5960X on principle. Anybody who's adopting X99 for productivity purposes will not skimp on core count and also go 5960X, especially considering they're likely to go at least 32GB RAM and therefore shelling out a lot of money. Those producing on CUDA cards may not even go X99 at all because 1150 Haswell has more than enough power to run the software. Folders and CUDA Miners similarly will want all GPUs running at full tilt so will likely invest in the 5960X to get all the PCI-E lanes.
So really, the only "smart choice" is 5960X or don't go X99 at all.