i7-5820: increased VCCSA for higher BCLK's?

The BIOS setting explanation for my Asrock x99 Extereme4 indicates higher VCCSA is beneficial for overclocking memory. Does VCCSA also affect stability for high BCLKS that result in high QPI & PCIe bus speeds?

It seems in my testing that I've had to use 1.4V VCCSA to get stability (using a 0.55 V VCCSA offset) on my Haswell-E rig when pushing the BCLK to 132MHz (which I need to push the memory to 2900 MHz).

Setting 1.4V VCCSA on X99 is like asking to kill IMC. Please read any basic overclocking guide before you burn anything on your rig.
1.1V VCCSA is enough for any memory configuration. VCCSA doesn't affect bclk. For bclk there are other settings and depends from board also additional PLL voltages. On the other hand bclk doesn't affect performance. It's useful only to tune memory/cpu settings but mainly in benchmarking.
Each strap is starting from 100MHz pcie and it's usually stable up to ~7MHz higher. 130-132MHz is on many boards limit for stable work.

Really stick to 100/125 bclk and play with cache frequency to raise performance a bit. At the same time check how high is working memory. Pushing bclk is waste of time and you can only corrupt BIOS or OS.

Quoting for importance..............

Setting 1.4V VCCSA on X99 is like asking to kill IMC. Please read any basic overclocking guide before you burn anything on your rig.

Click to expand...

So should the maximum voltage for VCCSA be kept @ 1.35V or less?

What exactly are the max voltages for Vcore, Vcache-uncore?

It looks like Vccin is never supposed to exceed 1.98V, but that's all the Intel whitepaper on the LGA2011-V3 seems to specify directly.

In the meantime, I'll drop my VCCSA offset to 0.4V and see if dropping my cache/uncore speed even further makes any diff. in stability.

The default cache speed for an i7-5820 is supposed to be 3300MHz right? The 3.6 GHz turbo frequency only applies to the CPU core frequency right? Or is the cache speed also boost to 3.6 GHz.?

Haswell-E is not like any previous series. VCCSA is not scalling above ~1.15V so there is no reason to set it above that regardless of memory config.

For 5820K@ ~4.7GHz, cache 4000MHz, 4x4GB DDR4 @3200 15-15-15 1.35V I'm using something like : 1.35V vcore, 1.0V VCCSA, 1.25V cache voltage, 1.9V VCCIN ( on worse chip 2.0V ).

Depends from CPU you may need VCCIN up to 2.1V for clocks above 4.7GHz and higher vcore.
How high can you set cache clock depends if your board has OC socket or not. If I'm right then yours doesn't have it so you will stuck at about 3.5-3.7GHz for full stability and for that it will need about 1.25-1.30V.

Re CPU OC, first you check how high vcore has to be. Then you check if higher vccin is helping to lower vcore. Best is to keep VCCIN below 2.1V and vcore below 1.4V for 24/7 work.

Default cache clock is 3.3GHz and turbo affects only cpu clock. However if you overclock it then best is to disable C states, EIST etc but keep Turbo enabled. Also set higher LLC to stabilize voltage.