Well i've just been digging around in the Crysis config files.
If you have a look in the config folder there are 2 sets of files, one for amd/ati cards and one for nvidia cards.
In each of these files it lists what default mode the card should run in.
Out of all the cards listed only 3 have setting 4 (highest) as their default.
Those cards are:
8800GTX
8800Ultra
And...
8800GT...
LOL the signs are not looking good for ATI's RV670 aka HD 3000 series, it hits the heady heights of 2 for the GFX settings in crysis, medium, yuk.

0x1002, 0x9400, 3 // ATI Radeon HD 2900 XT
0x1002, 0x9401, 3 // ATI Radeon HD 2900 XT
0x1002, 0x9402, 3 // ATI Radeon HD 2900 XT
0x1002, 0x9403, 3 // ATI Radeon HD 2900 PRO
0x1002, 0x9405, 3 // ATI Radeon HD 2900 GT
0x1002, 0x9500, 2 // RV670
0x1002, 0x9501, 2 // RV670
0x1002, 0x9505, 2 // RV670
0x1002, 0x9507, 2 // RV670
0x1002, 0x9580, 3 // RV630
0x1002, 0x9586, 2 // ATI Radeon HD 2600 XT AGP
0x1002, 0x9588, 2 // ATI Radeon HD 2600 XT
0x1002, 0x9587, 2 // ATI Radeon HD 2600 Pro AGP
0x1002, 0x9589, 2 // ATI Radeon HD 2600 Pro
0x1002, 0x94C4, 2 // ATI Radeon HD 2400 PRO AGP
0x1002, 0x94C1, 2 // ATI Radeon HD 2400 XT
0x1002, 0x94C3, 2 // ATI Radeon HD 2400 PRO
0x1002, 0x94C7, 2 // ATI Radeon HD 2350