i7 4790k
i7 4790k
Hello everyone. I purchased a fully functional i7 4790k to swap in for my i5 4460. After setup, temperatures remained high even when submerged. I began by separating the resistors next to the die, swapped the Intel TDP for liquid metal coolant, then reassembled everything using high-temperature silicon. The PC ran smoothly with stable temperatures and the new CPU performed well.
However, a few days later my motherboard stopped recognizing the CPU. I disassembled it again and discovered a single resistor wasn't properly isolated. After fixing it, the problem persisted. A few days on, I encountered another issue—another resistor failed to isolate properly. I repeated the process, but the same problem kept recurring.
Eventually, I decided to revert to using a standard non-conductive TPD in the PC. I cleaned the entire CPU and reassembled it, but the issue returned shortly after a week. I tried baking the CPU in an oven at 120°C for 30 minutes, which resolved the problem temporarily. Despite this, the recurring failures suggest a deeper hardware fault with the i7 unit itself.
Could anyone suggest further troubleshooting steps or potential causes? Thanks for your help, CreativeHiro.
Edit: I completely overlooked the need to recheck the i7 after multiple restarts (5 to 50). It seems it was detected again.
The oven setting wasn't sufficient for reflowing solder, likely resulting in no action. Uncertain about other possible causes.
The correct temperature would depend on the context, but generally it should be suitable for the intended use.
Did your motherboard show this pattern after switching to the 4790k but before you removed it? It seems unusual that you went straight to removing it once you noticed the high temperatures. I’d have checked for other reasons, like a misaligned or improperly secured waterblock, or a faulty loop/pump. The 4790k is indeed quite hot. I own one and used a 240mm AIO; under load, temperatures hit the mid to high 70s to low 80s. You’re likely aware of this, but here’s what the 4790k displays after delidding: two rows of resistors next to the die. It’s possible that during removal, some were cut off, which might prevent detection by your motherboard (are you seeing an error?). Another issue could be improper pressure on the die itself. Delidding voids the warranty because the adhesive used to bond the heatspreader to the substrate adds thickness to the package. A slight change in thickness could be affecting your setup. I recommend taking off the silicon adhesive and placing the IHS directly on the substrate, then securing it horizontally while closing the bracket. Reattach the waterblock and check for any blockages in your cooling loop. Best of luck!
You've confirmed the resistors are intact and the loop works as expected. I'm aware that using a lot of mounting pressure from the glue is something new for me, so I'll test this approach to see if it helps.
I don't know the typical number without looking it up, other than I know it is above 120C for old lead based solders. Newer lead-free ones melt at even higher temperatures. I'm not sure this is a meaningful route to go down. The oven trick is basically to melt the solder and allow it to reform, hopefully fixing any breakages that might not be visible. On a CPU, I'm not sure what they use to bond the die to the substrate, but the surface mount components do look like they may be soldered. If you have high enough magnification to see them you can at least do a good visual check of them first. I forgot about that, in part this is Haswell, and the mounting pressure I only recall reported on Skylake and newer as they used a thinner PCB for those which could bend under high pressure. Still, it is worth trying to alter the pressure to see if it helps.
I already disassembled my system once more and took a photo of the two rows of resistors. They seem undamaged to me. However, the mounting pressure feels like a solid reason. When I tested my CPU without any adhesive between the delamination and reassembly, it only booted when the heat spreader was perfectly centered.
Did you notice the motherboard failing to recognize the CPU in this setup? Keeping the IHS secure within the socket should work normally, but I'm curious if you begin encountering issues after a short period. Regarding your other concerns: Are you seeing any specific error indicators when the CPU isn't detected, and does this happen whether you're using Windows or just powering on the machine?
This behavior is unusual. When I keep the IHS fixed by the socket, the CPU only appears when it’s perfectly aligned. That aligns with the pressure it experiences. However, after turning it off for a while and then turning it back on, the CPU disappears from detection. Occasionally it works for days before suddenly vanishing when I try to boot. This happens only when the PC is powered on. Once running, it stays stable at 4.5 GHz with all cores handling stress tests. No error messages appear, just red indicator lights that flash when issues arise. The one under the CPU glows when it isn’t detected. At least the manual confirms no CPU detection when that light is on.