z420/z620 overcklock

[rtibby]

Hi  Brian

Yes I know about the 5 pin / 4 pin issue with coolers. I intend to use the 5 pin connector from the original cooler , cut out wires and solder wires to the new cooler.

I know about the quad channel memory too. My Z420 just came with 2 stick of 8 Gb memory on it. My order of 8x4Gb HP 1866 ECC 1R8 unregistered memory its on its way (not cheap though -- 233pounds)

And I've just paid for an e5-1680v2 in the end today... especially for the higher overclocking speed,  85 deg CPU temperature instead of 70 and bigger cash memory.

Another issue with Z420 I've experienced , and I saw a few forum topics about it : the cooling HP management. In short , if CPU temperature is going up to , say 85 deg , fans are still almoast idle . So , the temperature/speed curve for the fans is way too flat in order to protect CPU.  I was even researching how to put an external fan controller.... What do you know about this ?  

Z420, e5-1650v2 , 16Gb RAM, GTX 1070

[Brian1965]

Hi Rtibby,

Since I'm using a water-block on the CPU and a remote radiator/fan/pump set-up, I opted to add a seperate temperature controller board,[edit] This is visible on some of the images I've prevously posted on the forum. I have also retained the fan from my original HP stock air cooler and remounted the fan to cool the voltage regulators that surround the CPU socket. I have a temperature sensor mounted on the back of the CPU water-block which reads the temperature and adjusts the fan speeds accordingly. I also decided to add some self-closing, quick release connectors so that I can disconnect the cooler for any maintenance or moving the Z620.

The Plumbing

The Plumbing

Custom made PCI bracket

Custom made PCI bracket

Tube and wiring pass-through

Tube and wiring pass-through

Temperature controller fitted

Temperature controller fitted

System primed and running

System primed and running

Front view

Front view

Rear view

Rear view

You can buy these temperature controller boards on ebay for less than £2 !!

[rtibby]

Hi Brian

Pretty cool what you have done there.

Now I can see you do have 3 fans connected to that fan controller. I do assume all 3 are the fans for your liquid cooling system.

I also assume you did leave all original fans of Z420 connected to the board... I mean front/back/CPU (which you say you changed position).

I am wondering if I can controle the Z420 front/back fans and CPU fan (the Noctua one I want to install) with that controller .......

I am thinking that disconnecting from motherboard the HP fans will give me the error on boot (can be bypassed pressing F1 as far as I know / or you can fool BIOS by connecting to earth some of the pins?) . Do you think fan management will work like this ? 

And about that controller, I found it on ebay . https://www.ebay.co.uk/itm/12V-DC-Fan-Temperature-Control-Speed-Controller-CPU-High-Temp-Alarm-PWM-P...

Reading description and settings of it , I see you can set switches TP1 and TP2 ON/ON and fans will start to accelerate from minimum speed at 60 deg to maximum speed at 90 deg. Can you confirm it will be a linear curve between these two temperatures ? (60 / 90 deg would be  in my opinion the best choice in case of a air cooler on e5-1680v2 CPU)

By the way using this nice controller I would sort out the 5 pin/4pin issue connecting a non HP cpu cooler.

On the other hand, using this controller for all fans in Z420 you rely only on the readings of that temperature sensor. Is it advisable/reliable? Readings are accurate enough and not lagging?

Z420, e6-1650v2 @ 4.1Ghz all cores/stock cooler, 16 Gb Ram, GTX 10709 , 1Tb SSD Samsung 860 Evo ,1.5 Tb HDD

[Brian1965]

Hi Rtibby,

The 3x 140mm fans are all connected to the FAN1 socket on the temperature controller board using a 3-way fan cable;

The pump is connected to the FAN2 socket. The potentiometer adjacent to the FAN2 socket allows manual speed control of this output. This is set at 100% for the pump to ensure constant maximum coolant flow in the loop. 

The thermostat display on the water reservoir is powered from the FAN3 socket as this also has a potentiometer for manual speed control. Again, this is set at 100% = constant 12v DC output, NOT pulsed.

Yes, all the original fans in my Z620 are still present. I removed the fan from the stock HP cooler and re-fitted the fan directly to the memory shroud using a small nut and bolt;

With regards to the temperature controller board, here are the settings I'm using;

TFL1 = ON (FAN1 output minimum speed set at 40%)

TP1 = OFF, TP2 = OFF (Accelerate from 40% speed at 35°C to 100% speed at 45°C), e.g. 70% speed at 40°C

BF1 = ON (Alarm if fans stall)

BF2 = ON (Alarm if pump stalls)

The reason I have the fans set at a minimum of 40% is simply because the Corsair ML (Magnetic Levitation bearing) fans are extremely quiet so I might as well)

The reason TP1&2 are set so low is because the temperature probe is mounted on the back of the water block, i.e. not in direct contact with the CPU, and there is a thermal lag when the CPU starts to heat up.

To be honest, the water temperature usually hovers around the 23.6°C mark when under normal use and maxes around 28°C under continuous heavy load, e.g. rendering for 8-12 hours. Maximum CPU temperature recorded is around 58°C even under extreme heavy load and below 30°C at idle.

[rtibby]

Brian you were right ... about the all core speed of overclocked Xeon in Z420.

After I did work out my cooling solution (on air !!!)  (see https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/Z420-Fan-control-s... ) I managed to overclock e5-1650v2 to 4.5Ghz on all cores all right.

I did some tests , and the outcome about CPU speed is the following:  it does stay on 4.5 Ghz on all cores when active cores is less than 6 and usage is less than 100%. Than I tested on CPU stress Prime95 . Setting on task manager the affinity you can set 1 core, than 2 ... and so on all over to 6 . 

And , for 1 core is still 4.5 Ghz , even for 2 cores . 3 cores is 4.2 , 4 cores is 4,1 or 4 ... and on all cores is going down to 3.8 Ghz as you said....

TDP is the limiting factor I think , not the cooling solution ... Because even though the CPu temperature was low due to a good cooling (below 60deg) still Bios is setting lower speed for CPU taking into account the load, the external temperature , CPU temperature and especially keeping the CPU under the 130w TDP limit...

Anyway , I was enjoying games on speed of 4.5Ghz on all cores for example because CPU load was only 35% maximum ...

And as I said before I was happy to see I can push  the e5-1650v2 on air cooliing to the range achieved by other users with HP liquid coolers.

Now next step will be to see how much my soon coming e5-1680v2 will overclock... with my present air cooling solution.

I even have some tiny hope I can go near to your custom liquid cooling speeds (lol).

Regards,

Tibby

Z420 , e5-1650v2 @ 4.5Ghz all cores , Air CPU Cooler, 32Gb RAM HP 1xR8 4x8Gb , GTX 1070 , 1Tb SSD Samsung Evo 860, 1.5Tb HDD

[Brian1965]

With regards to the all-core clock speeds for the Xeon CPU's, I found this table in the HP Z420 quickspecs;

If you look at the column "Intel Turbo Boost Technology" you will see 2 numbers. The first number is for the all-core clock speed multiplier and the second number is the single-threaded clock speed multiplier.

The E5-1650 v2 Xeon has a base clock speed of 3.5GHz, an all core clock speed of 3.6GHz (i.e. 3.5GHz + (1 x 100MHz) = 3.6GHz), and a single-threaded clock speed of 3.9GHz (i.e. 3.5GHz + (4 x 100MHz) = 3.9GHz).

The E5-1680 v2 Xeon has a base clock speed of 3.0GHz, an all-core clock speed of 3.4GHz (i.e. 3.0GHz + (4 x 100MHz) = 3.4GHz), and a single-threaded clock speed of 3.9GHz (i.e. 3.0GHz + (9 x 100MHz) = 3.9GHz).

[rtibby]

Nice informative table that one...

Comparing the 1650v2 with 1680v2 , I have both CPU's and I had to decide which to keep in my Z420 . 

Although the 1650v2 went up to 4.5 Ghz ( 1680v2 strangely only up to 4.4Ghz) and 1650v2 has higher all core clock speed , I kept the 1680v2 for overall better performance and 25Mb L3 cash , 2 more cores.

Now I still have a question for you Brian : do you know what is in fact the limiting factor set by BIOS?/Motherboard? when you set the all core speed in XTU?

For e.g. when I try to set 4.6Ghz on 1650v2 or 4.5Ghz on 1680v2 system is rebooting instantly , even though CPU temp is kept low by cooling , lower than 60 deg ... Or it's rebooting straight away even the CPU is cold... Or I can put it in other way : how come your system lets you set 4.8 Ghz by XTU in the first place?

Z420 , e5-1680v2 @ 4.4Ghz all cores , Air CPU Noctua Cooler, 32Gb RAM HP 1xR8 8x4Gb , GTX 1070 , 1Tb SSD Samsung Evo 860, 1.5Tb HDD

[Brian1965]

Are you applying some additional Turbo Voltage in XTU?

Please re-check my XTU guide on page 1 of this thread. My post prior to the XTU guide shows you the additional Turbo Voltage settings I am applying in XTU.

"Now I still have a question for you Brian : do you know what is in fact the limiting factor set by BIOS?/Motherboard? when you set the all core speed in XTU?

For e.g. when I try to set 4.6Ghz on 1650v2 or 4.5Ghz on 1680v2 system is rebooting instantly , even though CPU temp is kept low by cooling , lower than 60 deg ... Or it's rebooting straight away even the CPU is cold... Or I can put it in other way : how come your system lets you set 4.8 Ghz by XTU in the first place?"

Okay, a quick crash course in semiconductors. When you switch on a circuit, the voltage appears to switch on instantaneously. However, in reality the voltage ramps up from 0V to 1.3V in a very short space of time. (Remember we are talking about GHz frequencies = less than 0.000000001seconds between pulses). As you start to increase the clock speeds, (i.e. increasing the CPU frequency and shortening the length of each pulse), above the standard CPU stock speeds, there is a risk that the signal will not reach 1.3V before the signal is turned off. In real life, logic and memory circuits read 0 and 1 signals as a voltage range, e.g. any signal between 0 and 0.3V = 0 and any signal above 0.6V =1 - these are not the exact voltage ranges but listed as a guide). Increasing the Turbo Voltage helps to overcome this problem.

My 4.8GHz overclock wasn't exactly stable as the TDP limit was reached. Yes, I was able to run the Passmark test but any heavy loading on the CPU resulted in the system rebooting. I was able to get the system stable at 4.7GHz and under heavy loading with a peak TDP of 126W.

[rtibby]

Hi.

Yes I did use your table as a reference for voltage.

So currently I am applying 242 mV for 4.4Ghz on 1680v2

I am afraid more than 242 mV is not advisable.

I can see you went all over to 360mV for the 4.8Ghz ...

I might give it a try , just fir the sake of experimenting

Z420 , e5-1680v2 @ 4.4Ghz all cores , Air CPU Noctua Cooler, 32Gb RAM HP 1xR8 8x4Gb , GTX 1070 , 1Tb SSD Samsung Evo 860, 1.5Tb HDD

[rtibby]

I am experiencing some issues with XTU , tried several releases , same..

In short two issues:

1. XTU does recognise all 8 cores in "System Information" tab , but does allow me to overclock only on 6 cores...

2. After installing , both Basic and Advanced overclocking Tabs are working. After a while , both dissapear , I mean not there any more (see photos) . Reinstalling is fixing the issue.

Did you experienced same? Or have some ideas how to fix...

Z420 , e5-1680v2 @ 4.4Ghz all cores , Air CPU Noctua Cooler, 32Gb RAM HP 1xR8 8x4Gb , GTX 1070 , 1Tb SSD Samsung Evo 860, 1.5Tb HD

NOt able to access overclocking after a while . And showing only 6 cores OCShoe=wing all 8 cores ok