Question CPU upgrade - PC won't boot

[Bulhy]

Hello,

I decided to upgrade my current CPU with i7-4790. So I bought one and yesterday I tried to replace it. After replacing the CPU, the PC wouldn't boot up, so I figured I needed a BIOS update. I updated to the latest BIOS version (3.A) and tried again, didn't work. Also I tried booting with one RAM (one piece) in different slots, I tried unplugging the GPU, clearing CMOS via Jumper, nothing helped. Note, that in all scenarios my current i5-4440 booted perfectly fine, on the other hand the i7-4790 didn't boot single time. I got any beebs (sound warning signal) or any warning output on a display. What's also weird is the fact, that while booting with i5-4440, a LED on front of my case, that signalizes computer being powered on, shined as it should. But upon booting with i7-4790, the LED didn't even blink, simply nothing. All it does upon booting with the i7-4790 is all the fans are spinning (+ are backlit).

What's the probability of the CPU being dead? I bought it pre-owned and the previous owner has screens of PC running just fine with the i7-4790 + it worked just day before he sent it to me.

My current specs:
CPU: Intel Core I5 - 4440 3.1 GHz
RAM: ADATA XPG Gaming Series V2 8GB (kit 2x 4GB) 1600 MHz + Kingston HyperX Fury DDR3 8GB (kit 2x 4GB) 1600 MHz
GPU: MSI RX 480 GAMING X 8G
PSU: Seasonic S12II-620 620W Bronze
MB: MSI B85-G43
SSD: Samsung 850 EVO 250 GB Basic
HDD: Seagate Barracuda 7200.14 - 2TB + 2. Seagate HDD 500GB
CASE: Cooler Master HAF 912 Plus
Chladič CPU: Gelid Solution Tranquillo rev.2

Thanks in advance for any help.

 

[taeioum]

It definitely seems like it's dead. Your CPU should've worked without a BIOS upgrade, as it's of the same generation.

Have you tried using your 4440 again? I'm almost assuming you're posting this with that CPU running, but I'm not sure.

Have you tried reseating your CPU again? You have to be sure the CPU is placed correctly. While doing this, check the pins in your motherboard CPU socket, as some may have bent which may cause these issues.

 

[Bulhy]

No, it shouldn't. My BIOS didn't support Hashwell Refresh, those processor were supported since BIOS 3.7 (I had 3.4 or something like that). So it was necessary to update my BIOS.

Yes, I switched between both processors several times. I would say it is impossible to put the processor wrongly into a 1150 socket. Although I always check to be sure. The socket is perfectly fine. Still working with my i5

 

[Calvin7]

A quick look at the CPU Compatibility List shows that CPU is not supported.

The Haswell Refresh Processors

New SKU	Cores	Intel List Price
Intel Haswell Refresh CPU List (Desktop)
Core i5-4690T	4 / 4	$213
Core i7-4785T	4 / 8	$303
Core i7-4790	4 / 8	$303

Some motherboard manufacturers did not offer support for those "Refresh" line of CPUs.

 

[Bulhy]

What do you mean? The i7-4790 is supported by my motherboard.
Look at proper support page

Anyways, I solved the problem step by step:

• I downgraded the BIOS to version 3.7 with my old i5, which is the first BIOS version to support Hashwell refresh
• Unplugged all components and left the MB connect with PSU + 1 piece of RAM
• Installed the i7, put thermal paste and tightly installed the CPU fan
• I unplugged the MB button battery (with unplugged PSU) and let it out for a minute, plugged it back in after a while
• Plugged the PSU back in, powered the computer and it worked just fine
• Eventually I installed every remaining component one by one, untill all components were installed and connected (4 RAMs, 2 HDDs, SSD, CD/DVD mech., and GPU)

Maybe the BIOS downgrade or the batter unplug helped, I don't know, as it doesn't really matter now