Elitedesk 800 G3 SFF - 7700k stability + Motherboard Power Limitations

[gnarlycheese]

Hello,      (NonSequitur777, I hope you see this)

I will start with questions and then give specs.

I have an Elitedesk 800 G3 SFF and want to put a i7 7700k in it. I understand that the pc is not listed as compatible with the i7 7700k, but a user, NonSequitur777, got the 7700k working on his elitedesk 800 g3 sff. I also understand I will need to ensure the bios features enabled will also be supported by the 7700k. Also, I will be upgrading the cpu cooler if I get the 7700k.

Being a 91w cpu, I am worried about the motherboards ability to handle it in addition to a 70w gpu. Also, I understand the primary pcie slot is rated per the quickspecs for 35w, but I have been using a 70w gpu with no issues for a few days. I am willing to think this is ok because I can only find anecdotes of success, none of failure, with higher wattage gpus that only draw from the pcie slot. I also plan on modding the top panel to have 3 x 120mm fans to handle the heat.

So basically I am wondering if it is even possible for the i7 7700k to be stable on the motherboard, while taking into account the higher than normal power draw from the rest of the system. The below specs will also help explain why I am even considering this.

Specs:

HP Elitedesk 800 G3 SFF

Current CPU: i7 7700 - 65w

GPU: RTX 3050 6gb Low Profile Zotac - 70w (On the supposedly 35w slot)

RAM: 2 x 8GB Samsung (Forgot the speed)

PSU: HP OEM 400w PN 942332-001

Boot Drive: Crucial P3 500GB nvme

Additional Storage: 2 x 4TB HGST Ultrastar 7K4000

[NonSequitur777 · Accepted solution]

@gnarlycheese,

Welcome to our HP Community forum!

And so, I did see your post!  I wished that HP made available a better way to notify Experts such as me directly -but I digress.

Yes -I did get the i7-7700K working in my HP EliteDesk 800 G3 SFF upgrade project (all the way using the very same platform to my HP EliteDesk 800 G5 SFF upgrade project), so it is possible. Let me address your main concerns one by one:

1. CPU Compatibility (i7-7700K in EliteDesk 800 G3 SFF):

• The motherboard/BIOS (latest version) does recognize the i7-7700K.

• Power delivery isn’t officially rated for a 91-watt CPU, but in my testing it was stable as long as thermals were managed.

• Important: upgrade the CPU cooler. The stock low-profile heatsink is not adequate for the 7700K under sustained load.

 

2. PCIe Slot Power (GPU):

• Whilst the HP QuickSpecs list the x16 slot as “35W,” in practice the slot can deliver up to 75-watt (standard PCIe spec).

• I have run high-end GPUs that pulled ~75-watt from the slot sans any issues.

• Since you have the 400-watt OEM PSU (942332-001), you have more headroom compared to the base 240W PSU.

 

3. System Stability and Cooling:

• Your plan to add extra 120mm fans is spot-on -this SFF chassis is thermally cramped.

• With adequate airflow, the 7700K and your low-profile RTX 3050 should coexist just fine!

• Keep in mind: if you push the 7700K at sustained all-core loads, power draw will spike above 91-watt, but again, if you can keep your thermals in check i.e. improve the overall airflow inside your case, you should be A-OK.

 

4. Realistic Expectations:

• The i7-7700 (65-watt) you have now already does a solid job. However, the i7-7700K will provide a fairly significant performance increase.

• If you’re doing this for the fun/modding aspect -absolutely, it’s a fun project and it works!

• If you’re after maximum performance gains, the thermal/power limitations of the SFF chassis are still going to be the bottleneck.

---

Bottom line: Yes, the i7-7700K can run stable in the EliteDesk 800 G3 SFF, provided you:

• Use the latest BIOS (02.50) from here: HP EliteDesk 800 G3 Small Form Factor PC Software and Driver Downloads | HP® Support.

• Upgrade the CPU cooler,

• Improve chassis airflow (your 3×120mm fan mod should do it),

• Keep an eye on temps/power draw, and:

• Upgrade to Windows 11 (will post an additional post after this one how to do that).

Your 70-watt TDP GPU is within what the PCIe slot + 400-watt PSU can safely handle.

Kind Regards,

NonSequitur777

[NonSequitur777]

@gnarlycheese,

Firstly, upgrade your TPM 1.2 to TPM 2.0 -if you haven't done so already: Infineon TPM Security Update | HP® Support with download link: https://ftp.hp.com/pub/softpaq/sp87501-88000/sp87753.exe.

Download and run the corresponding SoftPac. Then go to C:\SWSetup and locate the folder with the SoftPac number (sp87753) and double click it for the user's guide how to update TPM.

Once done, there are a number of reliable and effective methods developed which will allow you to almost effortlessly upgrade your so-called "unsupported device" to Windows 11, such as this easy-to-follow YouTube instructional video shows: https://www.youtube.com/watch?v=lSrmhhigEhY&t=332s&ab_channel=Tips2Fix.

This method uses a clever Microsoft (Server) backdoor Windows 11 install method.

This works great: I have used it myself on a number of legacy HP desktops without any issues whatsoever.

I cannot emphasize enough that this particular W11 upgrade method is hard to beat in terms of simplicity!

The Tips2Fix approach basically modifies the Windows 11 install media by replacing just one file (appraiserres.dll) with the Windows 10 version, which instantly disables all TPM, CPU, and Secure Boot checks without extra prompts or tool-specific steps.

Unless Microsoft changes the installer logic in future builds, this file-swap method will likely remain the quickest workaround for unsupported hardware such as your HP EliteDesk 800 G3 SFF.

Anyway, in the off-chance you don't like W11, you have 10 days to roll back to Windows 10. After 10 days, unless you follow the steps outlined in this instructional video, you may need to do a fresh install of Windows 10. Either way, this video will show you what to do with easy-to-follow instructions: https://www.youtube.com/watch?v=2v9_-4JCh_U&ab_channel=Tips2Fix.

Kind Regards,

NonSequitur777