speeding up nvidia GeForce GT 640 on freebsd

[John]

Hello list,

Is there any way of speeding up GPU performance on freebsd10-stable with 
this card? Sometimes it seems slow at redrawing - for example if I have 
an xterm over a webpage in chrome - if I move the xterm, the outline of 
it can remain in the page for a few seconds. I know there are tools one 
can use on windows for doing this. Can this be done in FreeBSD?
I've pasted pciconf output below, if it helps:

vgapci0 at pci0:1:0:0:class=0x030000 card=0x26433842 chip=0x0fc110de 
rev=0xa1 hdr=0x00      vendor     = 'NVIDIA Corporation'
  vendor     = 'NVIDIA Corporation'
  device     = 'GK107 [GeForce GT 640]'
  class      = display
  subclass   = VGA
  bar   [10] = type Memory, range 32, base 0xee000000, size 16777216, 
  enabled
  bar   [14] = type Prefetchable Memory, range 64, base 0xd0000000, size 
  268435456, enabled
  bar   [1c] = type Prefetchable Memory, range 64, base 0xe0000000, size 
  33554432, enabled
  bar   [24] = type I/O Port, range 32, base 0xe000, size 128, enabled
  cap 01[60] = powerspec 3  supports D0 D3  current D0
  cap 05[68] = MSI supports 1 message, 64 bit enabled with 1 message
  cap 10[78] = PCI-Express 2 endpoint max data 256(256) link x16(x16)
               speed 2.5(8.0) ASPM disabled(L0s/L1)

  hdac0 at pci0:1:0:1:class=0x040300 card=0x26433842 chip=0x0e1b10de 
  rev=0xa1 hdr=0x00
  vendor     = 'NVIDIA Corporation'
  class      = multimedia
  subclass   = HDA
  bar   [10] = type Memory, range 32, base 0xef080000, size 16384, 
  enabled
  cap 01[60] = powerspec 3  supports D0 D3  current D0
  cap 05[68] = MSI supports 1 message, 64 bit enabled with 1 message
  cap 10[78] = PCI-Express 2 endpoint max data 256(256) link x16(x16)
               speed 2.5(8.0) ASPM disabled(L0s/L1)

thanks,
-- 
John