Murph_9000 wrote:
One possibility for a bad memory channel is a bad CPU mount. Either pin damage, uneven pressure, or too much pressure from the cooler.

The Intel LGA1700 clamping mechanism is essentially a bad bit of engineering design. You may wish to investigate the replacement "contact frames" which clamp the CPU with much more distributed and even pressure. Thermal Grizzly do probably the best one, or there's Thermalright with a more budget version. See various videos on YT for details, such as der8auer, Gamers Nexus, and Jayztwocents, amongst others.

Jay also did a video on too much cooler mounting pressure causing pin contact problems.

It could be a problem with the CPU or board, but a mounting problem is more likely (and can be an easy fix). Remount, carefully inspecting the extremely fragile pins in the socket, and don't clamp the cooler down excessively.

That is a very promising suggestion. I will try it this evening.

Watching der8auer's video about the contact frame, he also talks about very finesse amount of pressure when connecting the contact frame and he also says that too much pressure can cause loss of contact to memory and even no boot at all. I wonder how much more easier it would be in that case to switch to the contact frame from the standard mounting mechanism, in order to avoid memory issues.

I went for the Arctic Cooling II 280 AIO in my build. There is also some interesting (and somewhat strange) thing with it. There are several revisions of the cooler and manuals for each are available on their website. I have rev 4 with a LGA 1700 mounting included as an extra already in the box. The latest rev is rev 7.

When I compare the manuals for package contents and installation instructions between the versions I see one potentially important issue/question:
- Rev 4 + extra LGA1700 mount come with 2 sets of stand off screws: 14mm to be used for the older backplate (older sockets) and 13mm to be used by the new backplate from the LGA1700 mounting set
- Rev 7, which already supports 1700 and older by a single backplate, comes with only 1 size of the stand off screws, the lenght of which is not specified.

When I look at the design of the stand off screws, it seems like they can only go as deep as the motherboard allows, not influenced by the backplate. If this is true, then it would then follow that the Rev 4 + LGA1700 mount with 13mm stand off screws is potentially creating more pressure on the CPU compared to Rev 7. Now, I don't know the length of the Rev 7 screws, but if it is supposed to be compatible with older sockets, which in Rev 4 use 14mm screws, I would assume that the Rev 7 screws must be also 14mm or somewhere between 13 amd 14mm.

Should I try using the 14mm stand off screws to have smaller pressure on the CPU, even though the official manual indicates to use 13mm instead of 14mm?

Another thing with the AC AIO is that the tubes are quite stiff and when mounting the cooling plate the stiffness pushes the plate more to the left side. I am not sure if this is also a contributing factor to the issue with A1 and A2 sockets not working. If I release the screws on the plate somewhat, the pressure from the tubes alone can potentially cause the same issue. It all seems extremely delicate and fiddly to mount a cooler on the LGA 1700 CPUs.

Murph_9000 wrote:
I would stick with the recommended screws, just don't go after every last thread when tightening if it gets tight before the threads run out.

I acually called Arctic in Germany and talked with the support person. He suggested not go all the way to the "end" when tightening the cooler on the stand off screws. Also there are some washers that should be added under the screws, though in rev 4 they are stickers with seemingly variable thickness, depending where they end up. At least they seemed a bit flimsy when I first mounted the screws and when trying to eliminate issues, I actually removed them. This lowered the total height of the stand off screws by some fraction of a millimeter I think, so in fact it contributed slightly to the overtightening.

Other interesting info I got is that the Rev 7 stand off screws are 12,9mm and the washers in that rev are plastic and reusable. They should be more reliable for the installation.

When analyzing the Thermal grizzly contact frame installation, it seems that the plate itself does not prevent the situation where the cooler gets overtightened because the frame does not rest on the board. So I think I will try first the standard mount with less tightening. I am really looking out with hope that this will solve my problem and I will not need to RMA the parts and wait for replacements.

I just wanted to state that this is also an issue I'm having with my setup as well and have the two slots on the left empty as well (I have 4 RAM sticks but only 2 installed). The only thing is that I'm using the ASUS ROG STRIX Z690-E GAMING WIFI