Question GPU PCIe 4 in a PCIe 3 slot

Oct 2, 2022
This question seems to have been answered, but before I clik "BUY" on a CA $1200 gpu, I want to be sure:
I have an ASUS z370-E mobo, and am looking to buy this gpu which states it is PCIe 4:
Will it work on this mobo? How much am I losing by it not being a PCIe 4 slot?
I am buying it specifically to play MS flight sim 2020
i7 8700K cpu, 32 gigs ram
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Which GPU model are you actually buying ? It should work on your mobo regardless.

A PCIe 4.0 graphics card will work in a PCIe 3.0 motherboard slot at PCIe 3.0 speeds. For PCIe 4.0 graphics cards, maximum graphics throughput can only barely exceed that of PCIe 3.0. For this reason, the benefits of upgrading your motherboard to PCIe 4.0 will be minor.

PCI-Express versions are also backward compatible, meaning that you can use a PCIe 4.0 graphics card or storage device on a PCIe 3.0 or PCIe 2.0 system. However, PCI-Express will use speeds based on the lowest of the two versions for communication. For example, if you use a PCIe 4.0 video card with a PCIe 3.0 system, the video card would be running at PCIe 3.0 speeds.

Reducing the PCIe version would halve the max potential bandwidth. However, you may not experience a performance impact if your device is not using the available bandwidth.

There are only a handful of graphics cards from the latest gen that make use of the PCIe 4.0 interface. Currently, both the latest high end NVIDIA and AMD graphics cards such as those from RTX 30 and AMD 6000 series make use of the PCIe 4.0 interface. As such, ideally the newer graphics should be plugged into motherboard that have the PCIe 4.0 slots.

However, if you only have a PCIe 3.0 slot, you can most certainly use these cards. And fortunately, as it stands, the performance drop from using the newer PCIe 4.0 GPUs in PCIe 3.0 slots is quite marginal, unless I'm mistaken.

PCIe 3.0’s throughput is 1GB per second per lane for an overall data transfer rate or bandwidth of up to 32 GB/s total. PCIe 4.0 doubles the 3.0 throughput rate per lane, giving us a transfer rate of up to 64 GB/s.
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