z420/z620 overcklock

[OmTatSat]

Glad to know that you successfully overclock your CPU!)

Already solved seems similar  problem after reboot and explained it here https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/z420-z620-overcklo...

[zack4485]

Anyone care to give some details on how they're achieving all-core overclocks on the 1680v2 that are effective even under load with 16 threads active?  My XTU settings of +4GHz work just fine until I fire up more than ~6 threads and then the CPU throttles back to ~3.65GHz.  My temperatures are under 60C so I don't imagine it's a temp problem.

[OmTatSat]

May be you reach TDP limit.

It seems to be posible in old samples CPUs.

My first CPU sample 1650v2 have also reach TDP limit. But my next sample of 1650v2 have no problem with reaching TDP limit, and it seems colder too.

Maybe it can be monitored by looking in stepping, but i don't realy sure about that.

[SDH]

Om, good idea, but I think it is something different...

There is only one sSpec code for the E5-1650 v2 processor, SR1AQ.  Also only one stepping, S1.  This is from the Intel "Ark" site when you look that processor up via google, pretty much always the top result.  I wish it was as easy as different sSpec codes.

For processor upgrades there sometimes are two or even 3 sSpec code... steppings.  More recent processors have trended towards there being only one.  If there is only one then it is the same processor.  I always look that up because I want to use the latest sSpec code/stepping if there are more than one for a particular processor.

Perhaps it is differences in the thermal paste or how it is applied.  I have posted here about the heatsink/fan from the Z440/Z640, which fits perfectly in the Z420/Z620..  For any of our high performance Z420/Z620 workstations I've been converting them over to that heatsink/fan instead of the original because those have almost exactly twice the heatsink cooling fin area, and a 4th heat tube instead of the normal 3 that come with the ZX20 "Performance" heatsink.  They fit perfectly... read those posts.

Finally, there are two types with same ID numbers.... I like the one with attachment by 2 screws front/back rather than two in the back.  Same fan for all practical purposes.  Lots more TDP head room if you are pushing things with either of those....

[OmTatSat]

May be you are right.

Just wrote what happened to me.

In detail.

When i waned to bought motherboard z420 with 1650v2 CPU, i asked seller to give me access to PC with this main parts through internet via TeamViewer. First time when i have access to pc, overclock was poor i described it in this thread. Then seller have got the another 1650v2 he told that it is newer. And after some time he tell me that new CPU is capable to more overcklock with less temperature and not mention that he have install new heatsink/fan or thermal paste, but of course i don't exclude the possibility of that by 100%.

[rtibby]

Hello

Brian said on page 1 of this post :

"Also, just to clarify, if you are running all the CPU cores simultaneously (at the same time), the maximum CPU clock speed is limited to 3.4GHz (E5-1680v2), regardless of the multiplier setting in XTU"

Is that true for every Xeon CPU's? I mean the all core speed to be limited regardless the multiplier set with XTU?

I do have a e5 1650v2 . Where can I find the all core spped limit ? (on ark site speed are for 1 core)

Also Brian when you say you achieved 4.8 Ghz you mean single core speed??

[Brian1965]

Hi Rtibby,

"Also Brian when you say you achieved 4.8 Ghz you mean single core speed??" = Yes, this is single core speed.

The simple answer is no, you cannot change the all-core maximum clock speed using XTU on the Z series workstations. You can of course increase the multiplier settings for up to 6 cores, as well as adjusting the Turbo Voltage setting. To be honest, I'm not sure if this is a limitation of the HP motherboard, (workstations as opposed to 'consumer' motherboards), or the fact that it is a Xeon CPU, (i.e. not a 'consumer' CPU either).

As a general rule, CPU's are usually overclocked using the BIOS and as you are aware, there are no BIOS overclocking settings on any of the Z series workstations. These systems were obviously designed for 24/7 reliability so the last thing the HP engineers want is anyone tinkering with the clock speeds. You can't even play with DRAM timings either.

However, I have heard of individuals using the 1680 V2 CPU's on consumer motherboards, such as ASUS, etc., which do have BIOS overclocking in-built. Again, I'm not sure if even they are able to increase beyond the default x34 multiplier when running 7 or 8 cores, (since it is a Xeon CPU). However, the all-core clock speed can be increased by increasing the motherboards base clock speed (>100MHz) on these consumer motherboards which you cannot do on the Z series workstations. i.e. if you were able to increase the base clock to 115MHz for example, then your all-core clock speed would be 115 x 34(max multiplier) = 3.91Ghz

You can use a HW monitoring program to determine your all-core clock speed. i.e. Run CPUID HWMonitor then run the Passmark CPU test and you should see the maximum single-core and the maximum all-core clock speeds.

[rtibby]

Thanks Brian for reply.

I understand now that overclocking for Z420 means actually the single core speed . As I understood there are decreasing core speeds according to number of cores used simultaneously.

For a particular CPU there are speed limits . Its not easy to find that information , I mean maximum speed / numer of cores used. It looks like Intel doesnt make that public.

In my case I have e5 1650v2 . Base clock 3.5Ghz , Turbo 3.9Ghz.

I don't know yet the maximum speed on all cores because for testing it I need to replace the stock HP CPU air cooler.

I do use XTU now with multipliers 42/1c - 40/2c - 39/3c- 39/4c - 38/5c - 38/5c (6192 TimeSpy score with GTX 1070).

When I do stress CPU on all cores , speed is 3.8 Ghz , but for the moment I dont know if thats because I use the 38 XTU multiplier or its is the limit of all core speed of the CPU/motherboard. I will test on higher XTU multipliers after replacing the CPU cooler. Here http://cpuboss.com/cpu/Intel-Xeon-E5-1650-v2 its stated that max overclock speed for this CPU is 4.21Ghz on air and 4.45Ghz water cooled . (I am wondering how do they know this with 2 decimal precision !?)

Speaking about replacing cooler , after reading all reviews and info I could find online , I opted instead of the HP liquid cooler the Noctua NH-U9DX i4 High Performance LGA2011 CPU Cooler . If I do belive reviews it will perform same as a liquid cooler being more quiet and no risk of leaks . (and new - 6 years warranty) . I am curious after installing it if I can go for the water cooler advertised speed which is 4.45 Ghz....

And more on the topic of overclocking : setting up an M.2 NVMe I do consider is worthed only for those who do use desktop as a server , or work with very large files, or do video editing. For just gaming, Windows use , boot speed, the increase is kinda max 3% ... not worthed.Better use a bigger quality SATA SSD . (I installed a 1Tb Samsung Evo SSD - works very nice and fast ) . To give an example Win10 boot is just 0.25 sec faster with M.2 NVMe .

About CPU's for my Z420 , replacing e5-1650v2 with the best CPU for this PC I mean e5-1680v2 I can see it will go up from 6192 TimeSpy score to 7000 on maximum overclock .... I am really wondering if it is worthed the extra 100GBP price difference. I am not doing video editing, just using normal Win softwares / gaming sometimes/ browsing/multimedia and CAD sometimes.

HP Z420 , Xeon 1650v2 , Noctua NH-U9DX i4 CPU cooler, 16Gb RAM (2x8Gb), 1Tb Samsung Evo 860 , GTX 1070

[rtibby]

Update to previous post:

I did set 4.1 Ghz on all cores with XTU.

Started CPU stress test and monitored actual speed with 1 active core , 2 , and all 6 in the end.

Speed was 4.1 Ghz regardless on number of cores. So even on all cores.....

That means (Brian !) that the CPU does respond accordingly to multiplier set with XTU even on all cores ....

What about the CPU/motherboard limit than ?? 

HP Z420 , Xeon 1650v2 , Noctua NH-U9DX i4 CPU cooler, 16Gb RAM (2x8Gb), 1Tb Samsung Evo 860 , GTX 1070

[Brian1965]

Hi Rtibby,

A couple of points:-

1. It is not as straight forward to simply remove the HP stock cooler and add a non-HP cooler. The HP cooler has a special 5-pin connector so you may need to do a little modding. I'm sure this has been explained on the forum before so you'll have need to do a quick search for the correct pin-outs.

2. I'm surprised to note that your only have 2 DIMMS installed in your set-up (2 x 8GB)? Your CPU supports 4 memory channels. Since you're not using all the CPU's available memory channels, you're not getting 100% performance from the CPU.  i.e. having 4 x 4GB DIMMS is better than 2 x 8GB DIMMS.

3. Regarding the maximum OC'd speeds on air and water, I suspect these values are average values from multiple benchmark results. e.g. some people will getter higher clock speeds and some people will get lower clock speeds. The cooler the CPU - the higher you can overclock. The bigger the cooling system, the better the cooling. e.g. I am able to OC to 4.8GHz since I have a large 420mm radiator with 3 x 140mm Corsair ML fans, large reservoir and high flow pump.

4. For gaming, I would be focusing purely on single threaded performance as this determines your graphics cards performance. and hence higher frame rates.