Han salido los nuevos y tan esperados drivers de Nvidia que -teoricamente- corrigen el problema del bajo uso de GPU en Assassins Creed IV, esperemos que sea cierto.

Sin más preambulos, acá estan los link a los drivers:

Win Vista/7/8 64-bits
Win Vista/7/8 32-bits

XP 32-bits
XP 64-bits

Notebook 64-bits
Notebook 33-bits

International Vista/7/8 64-bits
International Vista/7/8 32-bits

Release notes en inglés:

New in GeForce R331 Drivers

Performance Boost – Increases performance by up to 50% for GeForce 400/500/600/700 series GPUs in several PC games vs. GeForce 327.23 WHQL-certified drivers. Results will vary depending on your GPU and system configuration. Here is one example of measured gains:

GeForce GTX 770/780/TITAN/780Ti:
Up to 50% in Metro: Last Light
Up to 26% in Crysis 3
Up to 18% in Battlefield 4
SLI Technology
Assassins Creed IV: Black Flag – updated profile
Path of Exile – added profile
Natural Selection – updated profile
3D Vision
Assassins Creed IV: Black Flag – “Good”
Gaming Technology
Enables GeForce ShadowPlay™ technology
Call of Duty: Ghosts – added TXAA support (disabled FXAA)
SHIELD
Enables NVIDIA GameStream™ technology

Additional Details

Installs new PhysX System Software 9.13.0725.
Installs HD Audio v1.3.26.4
GeForce Experience 1.7.1 (v9.3.21.0)
Includes support for applications built using CUDA 5.5 or earlier version of the CUDA Toolkit. More information at http://developer.nvidia.com/cuda-toolkit
Supports OpenGL 4.3 for GeForce 400-series and later GPUs.
Supports DisplayPort 1.2 for GeForce GTX 600 series GPUs.
Supports multiple languages and APIs for GPU computing: CUDA C, CUDA C++, CUDA Fortran, OpenCL, DirectCompute, and Microsoft C++ AMP.
Supports single GPU and NVIDIA SLI technology on DirectX 9, DirectX 10, DirectX 11, and OpenGL, including 3-way SLI, Quad SLI, and SLI support on SLI-certified Intel and AMD motherboards.

Supported products

GeForce 700 series:
GTX TITAN, GTX 780 (Ti), GTX 770, GTX 760GeForce 600 series:
GTX 690, GTX 680, GTX 670, GTX 660 Ti, GTX 660, GTX 650 Ti BOOST, GTX 650 Ti, GTX 650, GT 645, GT 640, GT 630, GT 620, GT 610, 605GeForce 500 series:
GTX 590, GTX 580, GTX 570, GTX 560 Ti, GTX 560 SE, GTX 560, GTX 555, GTX 550 Ti, GT 545, GT 530, GT 520, 510

GeForce 400 series:
GTX 480, GTX 470, GTX 465, GTX 460 v2, GTX 460 SE v2, GTX 460 SE, GTX 460, GTS 450, GT 440, GT 430, GT 420, 405

GeForce 300 series:
GT 340, GT 330, GT 320, 315, 310

GeForce 200 series:
GTX 295, GTX 285, GTX 280, GTX 275, GTX 260, GTS 250, GTS 240, GT 240, GT 230, GT 220, G210, 210, 205

GeForce 100 series:
GT 140, GT 130, GT 120, G 100

GeForce 9 series:
9800 GX2, 9800 GTX/GTX+, 9800 GT, 9600 GT, 9600 GSO, 9600 GS, 9500 GT, 9500 GS, 9400 GT, 9400, 9300 GS, 9300 GE, 9300, 9200, 9100

GeForce 8 series:
8800 Ultra, 8800 GTX, 8800 GTS 512, 8800 GTS, 8800 GT, 8800 GS, 8600 GTS, 8600 GT, 8600 GS, 8500 GT, 8400 SE, 8400 GS, 8400, 8300 GS, 8300, 8200 / nForce 730a, 8200, 8100 / nForce 720a

ION series:
ION LE, ION