After the presentation and imminent arrival on the market of the RX6500XT everything seems rosy for users who either do not want to jump through the hoops of speculation, or do not have enough money to purchase a superior model. The fact is that new reports cite a possible problem with this GPU that we already saw in the RX 5500 XT at the time. Is PCIe 3.0 insufficient for this new model?
In just two days we will have the first analyzes of this new GPU under our belt, data and more data to analyze about what AMD understands by low-end in this 2022 and therefore a series of cards that will arrive at “affordable prices”. The problem is that they will launch with a PCIe 4.0 bus limited to x4 physically and the data, although it is collected and completed (it is not allowed to show it by signed NDA) seems to show a previous problem and that it will be repeated.
Bus limitation and performance on the RX 6500 XT PCIe x4
We start from the basis that we know the speeds of PCIe 4.0 and 3.0 in their different versions according to their lines, so really a x4 in the most current version is equivalent to eight lines of its predecessor in terms of available bandwidth.
But what about those users who want to upgrade their GPU and only have PCIe 3.0 with four lanes under their belt (x4)? Well, if we extrapolate the data offered and compare them, we will see that we have a serious problem that with the RX 6500 XT will result in a Worrying drop in performance.
Considering that the RX 5500 XT came in a version with 4 GB of VRAM and 8 GB, it is evident that the PCIe 3.0 x4 is not enough to timely transfer data from the CPU and system RAM to the VRAM of said GPU. So the 8 GB version takes advantage of this by giving the bus more time to exchange information while it is stored in its memory.
Can the 16 MB of Infinity Cache alleviate this?
It seems that it could be, at least in part, it is necessary to take into account that the RX 6500 XT has 64 bit of bus and only gives 144GB/s of bandwidth, where an important part of this has to do with your memory of 18Gbps (It is the first that includes it within the entire 6000 series).
Although there are rumors that AMD would launch new versions of said RX 6000 with this VRAM speed (fear of Intel?) the truth is that the 16MB Infinity Cache they will be decisive in PCs with less bandwidth available for their PCIe. The problem is that, as we saw at the time with the RX 5500 XT (tested under 3.0 x16), there were significant differences between 4 GB and 8 GB, where our conclusion was to choose and recommend the model with the largest VRAM size.
The RX 6500 XT with PCIe 4.0 x4 will not arrive, except for a last minute surprise, with 8 GB versions, which encourages users with veteran PCs to make the jump to a newer platform if they want not to lose performance nothing else to puncture the card and after having left more than 300 euros in the minor of the 6000 series of the red team. Lawful? Each one will have their opinion, especially seeing what they have to play as a base.
