Hi, since there is a shortage of GPUs and hardware in general, I decided to buy i prebuilt PC from one of the most reputable store chains in our contry. They also test those computers so I thought everything will be ok. The PC consists of: MSI MAG X570 TOMAHAWK WIFI AMD Ryzen 7 5800X G.SKILL 32 GB KIT DDR43600MHz CL16 Ripjaws V MSI GeForce RTX 3070 SUPRIM X 8G WD Blue NVMe SSD 1 TB Samsung 980 PRO 1 TB SilverStone Decathlon 80 PLUS Gold Modular 850W Be quiet! Pure Base 500DX Black Be quiet! DARK ROCK PRO 4 The problem is white horizontal lines across the screen at POST screen and in Windows. The lines don't appear in BIOS and also didn't appear when I booted Windows 10 Pro for the first time, however resolution was set to 800x600 and in BIOS resolution seems to be lower also. Here are photos how it looks: https://imgur.com/a/JVo4KBu https://imgur.com/a/tlN6fnV I think they appear only when the monitor is set to native resolution of 1920x1080 and don't when resolutions is lower. I use a DisplayPort cable which is working with this monitor and a GTX 980. Another problem is code 43 in device manager under GeForce RTX 3070. When I tried to install the newest driver, it black screened when loading the new driver during installation and I had to turn off the PC. Since I don't want to void warranty, I didn't try to open a case and reseat the GPU, but at least the power PCIE cables look properly attached (the case has a glass window). Most likely I will RMA it but if you have any clue how to fix it without sending the computer back, I would appreciate it.