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Dismantling the 4090 ROG Strix is a reasonably straightforward process. There are ten Phillips head screws securing the metal backplate, which also adheres to the VRMs underneath. Once that's out of the way, there are four more screws that secure the heatsink to the GPU, and these are designed to be installed using a torque screwdriver to avoid overtightening. You'll also need to remove eight more screws on the IO bracket.
Once all of those screws are removed, a small amount of force should be sufficient to detach the GPU and PCB from the heatsink and cooling shroud. However, there are three cables — two for the fans, one for the RGB lighting — connected near the edge of the PCB, so make sure to disconnect those before fully pulling the PCB away.
One of the main reasons we wanted to disassemble the Asus ROG Strix card was to check the GDDR6X memory. It's labeled "D8BZC," which if you look at Micron's full GDDR6X part catalog corresponds to 21Gbps modules. That's all well and good, except the behavior of these chips leads us to believe that Micron is labeling some 24Gbps (D8BZF) chips as 21Gbps.
Asus RTX 4090 ROG Strix OC Manual Overclocking
We mention the memory in particular as our manual overclocking results were quite impressive, especially on the memory. The 4090 Founders Edition started to have stability issues and artifacting with a +1200 MHz memory overclock (23.4 Gbps effective). The MSI card showed artifacts at just +1000 MHz (23 Gbps effective). But this specific Asus ROG Strix card? We were able to push the memory slider in MSI Afterburner up to the maximum +2000 MHz (25 Gbps effective) and still didn't see any artifacts.
It wasn't fully stable at that setting, as FurMark crashed after a few minutes, but +1750 MHz (24.5 Gbps) ran the FurMark stress test for over 30 minutes without issue. And it wasn't just a matter of appearing stable while also running extremely hot, as HWiNFO64 reported maximum GDDR6X junction temperature of only 64C — just 4C hotter on the memory than at the stock 21Gbps setting.
As for the GPU, we managed a relatively stable +200 MHz in initial testing but eventually had to drop that to +180 MHz as we experienced a bit of instability. Without more voltage (likely via a hardware voltage mod), we couldn't quite get the card to a stable 3.0 GHz, but we did easily break 2.9 GHz.
The Asus ROG Strix let us increase the power limit to 120%. The MSI card limited us to just 110% while the Founders Edition allowed 133%. Given the MSI card supposedly starts at a 480W limit instead of 450W, that potentially gives the Founders Edition the highest power limit of basically 600W (598.5W), the MSI card tops out at 528W, and the Asus card seems to allow up to 540W. It's also possible the Asus card actually has a 480W base limit, which would mean a final limit of 576W.
Note also that we pushed up the fan speed curve quite a bit for this overclock, just to be safe. We set the base fan speed at 50% up to 30C, then a straight ramp in RPMs up to 100% at 70C. We ended up with fan speeds of around 80% during testing, which was not at all quiet, though we likely could have dropped those a bit with further tuning efforts.
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