Your system information

• Steam client version (build number or date): 1738889325
• Distribution (e.g. Ubuntu): CachyOS (Arch Linux), SteamOS
• Opted into Steam client beta?: Yes
• Have you checked for system updates?: Yes
• Steam Logs: steam-logs.tar.gz
• GPU: Intel Arc Graphics 130V / 140V @ 1.95 GHz [Integrated], AMD Z1 Extreme (Phoenix APU)

System:
  Host: msi-claw7-a2vm Kernel: 6.14.0-rc2-3-cachyos-rc arch: x86_64 bits: 64
  Console: pty pts/0 Distro: CachyOS
CPU:
  Info: 8-core model: Intel Core Ultra 7 258V bits: 64 type: MCP cache: L2: 14 MiB
  Speed (MHz): avg: 1243 min/max: 400/4700:4800:3700 cores: 1: 1243 2: 1243 3: 1243 4: 1243
    5: 1243 6: 1243 7: 1243 8: 1243
Graphics:
  Device-1: Intel Lunar Lake [Intel Arc Graphics 130V / 140V] driver: xe v: kernel
  Display: unspecified server: X.org v: 1.21.1.15 with: Xwayland v: 24.1.5 driver: gpu: xe
    tty: 306x55 resolution: 1920x1080
  API: EGL v: 1.5 drivers: iris,swrast platforms: gbm,surfaceless,device
  API: OpenGL v: 4.6 compat-v: 4.5 vendor: mesa v: 25.1.0-devel note: console (EGL sourced)
    renderer: Mesa Intel Graphics (LNL), llvmpipe (LLVM 19.1.7 256 bits)
  API: Vulkan v: 1.4.303 drivers: N/A surfaces: N/A
  Info: Tools: api: clinfo, eglinfo, glxinfo, vulkaninfo de: kscreen-console,kscreen-doctor
    wl: wayland-info x11: xdpyinfo, xprop, xrandr
Drives:
  Local Storage: total: 3.22 TiB used: 793.95 GiB (24.1%)
  ID-1: /dev/mmcblk0 model: SD1T5 size: 1.4 TiB type: Removable
  ID-2: /dev/nvme0n1 vendor: Crucial model: CT2000P310SSD2 size: 1.82 TiB

Please describe your issue in as much detail as possible:

When downloading large games to either my internal SSD (bcachefs) or to my microSD card (ext4) on this MSI Claw 7 AI+ A2VM, Steam shows a greatly inflated install size compared to what the download prompt for said games initially suggests. I tested this with a primary btrfs internal SSD partition, and that displayed the same behavior on this unit. I also see the issue on SteamOS Main with the same beta client on my ROG Ally X where the reported download size is 2* the actual installed size.

For example, Returnal says it will use 53.4 GiB once installed:

However, if I start the download, then prioritize a separate download, the "Up Next" section for game downloads instead shows the game will need 160.3GiB (3* the amount of storage from the previous prompt):

Once the game is finished installing, I can see that it does take up the expected 53.4 GiB leading me to believe the download page is just some sort of Steam client reporting error.

Let me know if any additional logging or system information would be helpful for diagnosing the issue.

Steps for reproducing this issue:

1. Start a game download for a large game and let it get past shader downloading
2. Start a second download to pause the first download

The reported size for the paused download show now be falsely inflated in the Steam UI.