Dynamic Parallelism and HyperQ, two features in GK110/GK208 GPUs, are also supported across the entire Maxwell product line. GM107 supports CUDA Compute Capability 5.0 compared to 3.5 on GK110/GK208 GPUs and 3.0 on GK10x GPUs. Also, each Graphics Processing Cluster, or GPC, contains up to 4 SMX units in Kepler, and up to 5 SMM units in first generation Maxwell. Nvidia claims a 128 CUDA core SMM has 86% of the performance of a 192 CUDA core SMX. SMM allows for a finer-grain allocation of resources than SMX, saving power when the workload isn't optimal for shared resources. Texture units and FP64 CUDA cores are still shared. These units are connected by a crossbar that uses power to allow the resources to be shared. This is in contrast to Kepler, where each SMX has 4 schedulers that schedule to a shared pool of 6 sets of 32 FP32 CUDA cores, 2 sets of 16 load/store units, and 2 sets of 16 special function units. The layout of SMM units is partitioned so that each of the 4 warp schedulers in an SMM controls 1 set of 32 FP32 CUDA cores, 1 set of 8 load/store units, and 1 set of 8 special function units.
The structure of the warp scheduler is inherited from Kepler, which allows each scheduler to issue up to two instructions that are independent from each other and are in order from the same warp. Nvidia also changed the streaming multiprocessor design from that of Kepler (SMX), naming it SMM. Accordingly, Nvidia cut the memory bus from 192 bit on GK106 to 128 bit on GM107, further saving power.
Nvidia increased the amount of L2 cache from 256 KiB on GK107 to 2 MiB on GM107, reducing the memory bandwidth needed. These new chips provide few consumer-facing additional features Nvidia instead focused on power efficiency. Main article: Maxwell (microarchitecture) First generation Maxwell (GM10x) įirst generation Maxwell GM107/GM108 were released as GeForce GTX 745, GTX 750/750 Ti and GTX 850M/860M (GM107) and GT 830M/840M (GM108).
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