PCIe 3.0 compatibility on Z68 board
PCIe 3.0 compatibility on Z68 board
I'm checking if switching from an i7 2600K to an i7 3770K on my ASUS P8Z68-V Pro would let me reach PCIE 3.0 speeds. I’m aware that some Z68 boards have updates for that, but my board isn’t one of those. I’m pretty sure no changes were made to enable 3.0 speeds, so it’s likely they only tested it.
What graphics card are you employing? Changing from 2600k to 3770k won't provide the 3.0 performance boost; it will merely settle around 2.0 speed like with your 2600k. As I mentioned, it really depends on the GPU you have—if you're using something like 970 or 980, the difference between 2.0 and 3.0 won't be noticeable.
The ASUS P8Z68-V Pro supports only PCIe 2.0. The ASUS P8Z68-V Pro/GEN3 offers Gen 3.0 performance. Installing a third-generation CPU won't enable PCIe 3.0 functionality.
The ASUS BIOS is being crossflashed, I’m curious if that would enable Gen 3 performance. Be aware ASUS sometimes has faulty or deliberately weakened BIOS on lower-end boards, so it might work. Since the BIOS chip is replaceable, you can purchase a programmer like the CH341A and upload the new BIOS for testing. It costs just $4 to check functionality, or you can upgrade to Deluxe for better OC potential (especially for RAM IDs). Buying an incremental upgrade for Gen 3 seems unnecessary—even a 3080 won’t run fully on an X16 Gen 2 slot, likely because of latency issues. The 3770K will need to be removed for the required 4.6GHz+ OC, and these platforms generally underperform when overclocked, so consider trading in or using a used AM4 board if you want to upgrade the CPU.
I've researched a bit and it looks like multi-GPU boards rely on a chip that divides the lanes. This component wasn't built for PCIe 3.0, so a 3770k won't unlock those speeds. Interestingly, motherboards with a direct CPU-to-PCIe connection can still run at 3.0 if the right CPU is present. I'm not concerned about top-tier GPUs; even a 2600k would limit something like a 3080 at 4k. My focus is on mid-range chips such as the 6600xt, which the older Sandy chip still manages, but PCIe 2.0 x8 becomes a limitation. Also, the 3770k seems to be a weak point. Any gains in IPC it offers are offset by slower raw clock speeds, and you'd need to desolder the chip to hit over 4GHz while it stays cold at 5GHz. PCIe 3.0 was the only real advantage I saw.
Sandy Intel began switching to a low-quality thermal paste instead of solder, making overclocking on old TIM challenging. Removing it is simple—just use a thin tool or a cheap delid kit. You can also stick with regular paste, though liquid metal is optional. Good thermal paste still works, but it’s not essential. The dried TIM you see is likely worth it only if you can get a better one, especially for high-performance builds. Intel’s 32nm and 22nm models run cooler than expected, but you won’t hit voltage limits unless pushing very high speeds.