[i12bp8]

6 GB cards (the RTX 3060 Laptop, 2060, 1660 and the like) start on the Low preset, whose 512 MB of mirrors leaves most of the game's memory pools out of VRAM: the GPU reads them over PCIe, 30-32 GB of bound ranges every 600 submits in Hyrule Field on an RTX 3060 Laptop. This gives those cards a quarter of the card, 1536 MB, on Low and on Auto alike: in Castle Town Market 20 → 22.4 fps, GPU 32 → 25 ms a frame, half the frames over 50 ms.

What changed

• The VRAM budget row's 3.6 GB step mirrors 1536 MB, not 512 (gpu/vk/vk_menu.cpp). It is the Low (6GB) preset's, which menu_first_start_for_gpu gives every dedicated card of 4.5-6.5 GB.
• Auto agrees (gpu/vk/mirror_budget.h, auto_bytes, used by mirror_budget in vk_memory.cpp): cards over 4.5 GB and up to 6.5 GB get a quarter (1536 MB on 6 GB; it was an eighth, 768). Cards of 4.5 GB or less keep an eighth (512 MB on 4 GB), larger ones a quarter up to 3 GB as before. The eighth on 6 GB cards was there because the image blocks made at the start sat empty beside the mirrors; since fix(vk): make the blocks at the start in the pool the textures are made in (#2690) #2711 they are made in the textures' pool.
• A preset's mirrors never pass Auto's on the card (preset_bytes, when a Quality preset set the budgets): Low on a 4 GB card, which preset_caps_memory lets through, or Minimum with the row moved to 3.6 GB, stays at 512. A budget chosen on the VRAM budget row itself stays the player's on any card (feat(menu): a VRAM budget row of its own (builds on #1358) #1859).
• tests/test_mirror_budget.py runs the rules and checks that mirror_budget uses them; tests/test_vram_budget_row.py has Low's 1536. docs/development.md says what RX_VK_MIRROR_MB defaults to.

Tested

Windows 11, RTX 3060 Laptop 6 GB (5.0-5.1 GB allowed), NVIDIA 621.14, Ryzen 7 6800HS, 16 GB. The first start's Low (6GB) budget, DLSS (1152x648 → 1536x864), Reflex on, Game speed Per frame (HOS_REALTIME_STEP=0). No window (HOS_HEADLESS), input through the control bridge: the debug teleport, then standing with the camera turning for 60 s. A = 51da046 + #2711, B = that + this; both renderers built with llvm-mingw (RX_VK_ONLY, RX_RELEASE=1, NVIDIA DLSS). main's own renderer (API 20, a new translator stamp) does not run against this PC's game and program cache, so the base is the installed build's plus #2711. Two runs each, in turn:

	A	B
Castle Town Market fps	20.2, 20.1	22.5, 22.3
GPU ms a frame	31.4, 33.5	24.6, 25.2
frames over 50 ms	1252, 1287	571, 616
driver's count at most / allowed (MB)	4669 / 5096, 4671 / 5064	5039 / 5096, 5233 / 5099
textures' budget (held)	1.98 (2.25), 1.99 (2.31) GB	1.08 (1.86), 1.03 (1.90) GB
textures made again empty	0, 3	0, 3
Hyrule Field fps	28.8, 29.3	29.1, 32.3
GPU ms a frame	24.0, 23.5	21.0, 18.7
frames over 50 ms	165, 134	34, 148
driver's count at most / allowed (MB)	5469 / 5039, 5359 / 5039	4988 / 5097, 4982 / 5103
textures' budget (held)	2.67 (1.82), 3.00 (1.89) GB	0.87 (1.29), 0.88 (1.29) GB
textures made again empty	6, 4	11, 11

The cost is the textures' budget: about 1 GB in the market and under 0.9 GB in Hyrule Field, where twice as many textures were made again in 60 s (headless: not looked at on screen). Earlier, on a scripted walk (main before #2711, the preallocation off by switch): 1536 MB took ~0 GB over PCIe every 600 submits against 30-32 GB, GPU 27 → 19.5 ms; 1024 MB gave 26.5 and 31.3 fps with the budget full and which pools stayed out varying.

• No device lost, no new error lines; the program cache kept (47866 keys).
• python -I -B tests/run_all.py on Windows: 472 passed, 10 failed, 41 skipped. The same 10 fail on main on this PC (symlink privilege, dotnet restore, no gcc, and test_readme_menu_rows: the Skip opening row has no README line).
• Rows in docs/tested-configurations.md.
• Nothing on screen changes: no screenshots.

Not tested: another 6 GB card (a desktop one with a display attached has less allowed), AMD (GCN keeps its mirrors off) and Intel, Linux, 4 GB cards (the cap keeps them at 512).

Overlap

• fix(menu): the presets' VRAM budgets stay within Auto's rule, and no preset sets the Profile #2676 maps Balanced to the 3.6 GB step and edits tests/test_vram_budget_row.py's preset table and the kVramMirrorMb line: whichever lands second updates them. With both, Balanced on an 8 GB card mirrors 1536 MB (Auto gives it 2048).
• perf(vk): mirror the pools the GPU reads most, in place of colder ones #1377 (the hottest pools mirrored first) chooses which pools a full budget keeps.

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[i12bp8]

Thanks for the review. Updated:

• (1) dropped, rebased on main (4cf785a) with fix(vk): make the blocks at the start in the pool the textures are made in (#2690) #2711 in. The PR is the mirrors alone now.
• Auto and Low agree (gpu/vk/mirror_budget.h, auto_bytes): cards over 4.5 GB and up to 6.5 GB get a quarter (1536 MB on 6 GB; it was an eighth, 768). 4.5 GB or less keep an eighth (512 on 4 GB), larger cards as before. The eighth on 6 GB cards was for the image blocks made at the start, which fix(vk): make the blocks at the start in the pool the textures are made in (#2690) #2711 now makes in the textures' pool; the comment says so.
• A preset's mirrors never pass Auto's on the card (preset_bytes, when opts.budget > 0): Low on a 4 GB card, or Minimum with the row moved to 3.6 GB, stays at 512. A budget chosen on the row itself stays the player's, as feat(menu): a VRAM budget row of its own (builds on #1358) #1859 has it.
• tests/test_mirror_budget.py runs the rules and checks that mirror_budget uses them. run_all on Windows (on 3723fd0, the VRAM checks again on 4cf785a): 472 passed, 10 failed, 41 skipped; the same 10 fail on main on this PC (test_readme_menu_rows there too: the Skip opening row has no README line).

#2711 alone (A) against #2711 + this (B), RTX 3060 Laptop, Low, DLSS, standing with the camera turning for 60 s, two runs each in turn. Built on 51da046 + #2711: main's renderer is API 20 with a new translator stamp, which this PC's game and program cache don't take.

	A	B
Castle Town Market fps	20.2, 20.1	22.5, 22.3
GPU ms a frame	31.4, 33.5	24.6, 25.2
frames over 50 ms	1252, 1287	571, 616
driver's count at most / allowed (MB)	4669 / 5096, 4671 / 5064	5039 / 5096, 5233 / 5099
textures' budget (held)	1.98 (2.25), 1.99 (2.31) GB	1.08 (1.86), 1.03 (1.90) GB
textures made again empty	0, 3	0, 3
Hyrule Field fps	28.8, 29.3	29.1, 32.3
GPU ms a frame	24.0, 23.5	21.0, 18.7
frames over 50 ms	165, 134	34, 148
driver's count at most / allowed (MB)	5469 / 5039, 5359 / 5039	4988 / 5097, 4982 / 5103
textures' budget (held)	2.67 (1.82), 3.00 (1.89) GB	0.87 (1.29), 0.88 (1.29) GB
textures made again empty	6, 4	11, 11

You were right that the textures' budget is what gives: about 1 GB in the market and under 0.9 GB in Hyrule Field, where twice as many textures were made again (11 against 4-6 in 60 s; headless, so I haven't looked at them on screen). The market, the heavier spot, is the clearer win: +11% fps, GPU -24%, half the long frames, no more textures made again. With #2711 alone the driver's count went past the allowance in Hyrule Field (5.36-5.47 of 5.04 GB); with this it stayed under there and reached it in the market.

Not done: another 6 GB card, or AMD. I can't run those here; a tester with a 2060, a 1660 or an RX 5600 XT on the same two spots would settle it. If the texture side needs holding back, the two things I'd measure next are RX_VK_MIRROR_TIGHT on for these cards, or 1024 MB (26.5 and 31.3 fps on my first walk, with the budget full and which pools stayed out varying).