Usability ratings are calculated by the following formula:

Pšuse = ((((C10xp^0.6 * C12xp^0.3 * P¡16xp^0.1) *
      (HL10xp^0.6 * HL12xp^0.3 * HL16xpxp^0.1) *
      (U210xp^0.6 * U212xp^0.3 * U216xp^0.1) *
      (TRAOD10xp^0.6 * TRAOD12xp^0.3 * TRAOD16xp^0.1) *
      (FC10xp^0.6 * FC12xp^0.3 * FC16xp^0.1) *
      (RM10xp^0.6 * RM12xp^0.3 * RM16xp^0.1) *
      (D310xp^0.6 * D312xp^0.3 * D316xp^0.1) *
      (PK10xp^0.6 * PK12xp^0.3 * PK16xp^0.1) *
      (G110xp^0.6 * G112xp^0.3 * G116xp^0.1) *
      (G210xp^0.6 * G212xp^0.3 * G216xp^0.1) *
      (G310xp^0.6 * G312xp^0.3 * G316xp^0.1))^(1/11) *
      (C10aaaxp * HL10aaaxp * U210aaaxp * TRAOD10aaaxp * RM10aaaxp * FC10aaaxp * D310aaaxp * PK10aaaXP * AAA) ^ (1/8)) ^ 0.7 *
      (Poss ^ 0.3)) / (Price + APG)) * 2

The similar calculation (but for 1600x1200 resolution only) indicates the prospect of a videocard. The formula contains the same indexes as those used for usability rating calculations, but accelerator's price isn't considered. So, this rating indicates the capabilities of the current 3D cards in the current applications and future games.

Pšpro = (((P¡16xp *
      HL16xpxp *
      U216xp *
      TRAOD16xp *
      RM16xp*
      D316xp*
      PK16xp*
      FC16xp*
      G116xp*
      G216xp*
      G316xp)^ 0.7 *
      (Poss ^ 0.3)) * 10

You can also compare two ratings to see the correspondence of product prices to their capabilities and features.

Sergey Gajdukov suggested the nonlinear relation calculation method, which we use now (it's also provided in Excel table). Kuse is calculated using the similar formula, but each FPS value is not entered as is, but calculated like shown below:

FPSnew = 50 * (ATAN (FPSold / 30 - 2) - ATAN (-2)) + FPSold / 100

This relation has the following properties:

1. In the 0..20 range FPSnew is much smaller than FPSold ("low performance penalty")
2. In the 20..60 range the following should be true: FPSnew < FPSold
3. In the 60..120 range both values are approximately equal, i.e. the function is almost linear.
4. At x > 120 the function should grow VERY slowly

This method was used to get usability coefficient in case of dividing by card price (without upgrade additions. The legend:

• Kuse - usability rating. The higher it is, the better card's mark is.
• Kpro - prospect rating. The higher it is, the better card's mark is.
• C10xp - speed in Call of Duty (ixbt0104) at 1024x768x32 (Windows XP);
• C10aaaxp - speed in Call of Duty (ixbt0104) at 1024x768x32 (Windows XP) and AA+Aniso;
• C12xp - speed in Call of Duty (ixbt0104) at 1280x1024x32 (Windows XP);
• C16xp - speed in Call of Duty (ixbt0104) at 1600x1200x32 (Windows XP);
• HL10aaaxp - speed in Half Life 2 beta at 1024x768x32 (Windows XP) at max. quality and AA+Aniso;
• HL10aaaxp - speed in Half Life 2 beta at 1024x768x32 (Windows XP) at max. quality and AA+Aniso;
• HL12xp - speed in Half Life 2 beta at 1024x768x32 (Windows XP) at max. quality;
• HL16xpxp - speed in Half Life 2 beta at 1600x1200x32 (Windows XP) at max. quality;
• U210xp - speed in Unreal 2 at 1024x768x32 (Windows XP);
• U210aaaxp - speed in Unreal 2 at 1024x768x32 (Windows XP) with AA+Aniso;
• U212xp - speed in Unreal 2 at 1280x1024x32 (Windows XP);
• U216xp - speed in Unreal 2 at 1600x1200x32 (Windows XP);
• TRAOD10xp - speed in Tomb Raider: The Angel of Darkness (Paris5_4 demo) at 1024x768x32 (Windows XP);
• TRAOD10aaaxp - speed in Tomb Raider: The Angel of Darkness (Paris5_4 demo) at 1024x768x32 (Windows XP) and AA+Aniso;
• TRAOD12xp - speed in Tomb Raider: The Angel of Darkness (Paris5_4 demo) at 1280C...1024C...32 (Windows XP);
• TRAOD16xp - speed in Tomb Raider: The Angel of Darkness at 1600C...1200C...32 (Windows XP
• RM10xp - speed in RightMark at 1024x768x32 (Windows XP);
• RM10aaaxp - speed in RightMark at 1024x768x32 (Windows XP) with AA+Aniso;
• RM12xp - speed in RightMark at 1280x1024x32 (Windows XP);
• RM16xp - speed in RightMark at 1600x1200x32 (Windows XP);
• FC10xp - speed in FarCry at 1024x768x32 (Windows XP);
• FC10aaaxp - speed in FarCry at 1024x768x32 (Windows XP), AA+ANISO;
• FC12xp - speed in FarCry at 1280x1024x32 (Windows XP);
• FC16xp - speed in FarCry at 1600x1200x32 (Windows XP);
• D310xp - speed in DOOM III at 1024x768x32 (Windows XP);
• D310aaaxp - speed in DOOM III at 1024x768x32 (Windows XP), AA+ANISO;
• D312xp - speed in DOOM III at 1600x1200x32 (Windows XP);
• D316xp - speed in DOOM III at 1600x1200x32 (Windows XP);
• PK10xp - speed in Painkiller at 1024x768x32 (Windows XP);
• PK10aaaxp - speed in Painkiller at 1024x768x32 (Windows XP), AA+ANISO;
• PK12xp - speed in Painkiller at 1280x1024x32 (Windows XP);
• PK16xp - speed in Painkiller at 1600x1200x32 (Windows XP);
• G110xp - speed in 3DMark05 Game1 at 1024x768x32 (Windows XP);
• G112xp - speed in 3DMark05 Game1 at 1280x1024x32 (Windows XP);
• G116xp - speed in 3DMark05 Game1 at 1600x1200x32 (Windows XP);
• G210xp - speed in 3DMark05 Game2 at 1024x768x32 (Windows XP);
• G212xp - speed in 3DMark05 Game2 at 1280x1024x32 (Windows XP);
• G216xp - speed in 3DMark05 Game2 at 1600x1200x32 (Windows XP);
• G310xp - speed in 3DMark05 Game3 at 1024x768x32 (Windows XP);
• G312xp - speed in 3DMark05 Game3 at 1280x1024x32 (Windows XP);
• G316xp - speed in 3DMark05 Game3 at 1600x1200x32 (Windows XP);
• Price - card price for the end of the month taken from price lists of a number of companies (for an average card);
• APG - see above;
• Poss - estimated functional potential and quality of a videocard (see remarks below);

Poss is calculated by the following formula:

Poss = (Driver * AF * TLF * DOT3 * EMBM * CEM * AA * S3TC * VS * PS * 3dc * DH) ^ (1/11)

Where:

• Driver - estimated drivers quality (including installation difficulties, etc.) on the 1000-mark scale.
• AF - anisotropic filtering:
  • = 700 - available;
  • = 0 - n/a;

• TLF - trilinear filtering:
  • = 600 - available;
  • = 200 - potentially available with resource losses;
  • = 150 - approximation;
  • = 0 - n/a;

• DOT3 - Bump Mapping DOT3:
  • = 600 - available;
  • = 0 - n/a;

• EMBM - Bump Mapping EMBM:
  • = 600 - available;
  • = 0 - n/a;

• CEM - Cubic Environment Mapping:
  • = 600 - available;
  • = 0 - n/a;

• AA - antialiasing (on condition of minimal gameplay):
  • = 700 - MSAA;
  • = 1000 - MSAA+SSAA;
  • = 0 - n/a;

• S3TC - texture compression:
  • = 1000 - RADEON X700/800 - 3Dc;
  • = 600 - RADEON 9600/9700/9800/X800, GeForce FX/6800;
  • = 0 - n/a;

• VS - hardware vertex shaders:
  • = 1200 - version 3.0;
  • = 1000 - version 2.0b;
  • = 600 - version 2.0;
  • = 0 - n/a;

• PS - hardware pixel shaders:
  • = 1200 - version 3.0;
  • = 1000 - version 2.0b;
  • = 600 - version 2.0;
  • = 0 - n/a;

• DH - additional features: dual-monitor output with the support of DualHead/TwinView/HydraVision technologies, TV-tuner, etc.:
  
  
  • = 700 - RADEON 9600/9700/9800/X800, GeForce FX/6800;
  • = 0 - n/a;

P.S. We understand that such way of making ratings is not perfect, therefore we await suggestions and comments from our readers to be considered in our next 3Digest.