title: My limited FPS : 60
body: <p>I have learn OpenGL programming for some time.And I found a very strange phenomenon : my FPS(Frame per Second) always stays about 60,no matter the program is very easy or a little complicated.Actually,my computer is bought last year and the performance is good.The graphics card is nVidia GTX570,CPU is I7.</p>
  
  <p>So I make a experiment:run the same program on my computer and my friend's computer.This program implements shadow mapping:</p>
  
  <p><img src="https://i.stack.imgur.com/PgSG6.jpg" alt="enter image description here"></p>
  
  <p>The FPS in my computer is about 60.
  But when I run it in my friend's computer,The FPS is more than 400.
  <img src="https://i.stack.imgur.com/CwM3u.png" alt="enter image description here"></p>
  
  <p>But my computer's performance is obvious better than his.Now I post our computer's parameter.</p>
  
  <p>My computer:</p>
  
  <pre><code>tgt.init (Info)  GLEW version: 1.7.0
  tgt.GpuCapabilities (Info)  OS version: Windows 7 (build 7600)
  tgt.GpuCapabilities (Info)  OpenGL Version: 4.2.0
  tgt.GpuCapabilities (Info)  OpenGL Renderer: GeForce GTX 570/PCIe/SSE2
  tgt.GpuCapabilities (Info)  GPU Vendor: NVIDIA Corporation (NVIDIA)
  tgt.GpuCapabilities (Info)  Texturing: yes, max size: 16384, 3D: yes, max 3D size: 2048
  tgt.GpuCapabilities (Info)  Texture features: 32 units, NPOT, rectangles, compression, 16x anisotropic
  tgt.GpuCapabilities (Info)  Framebuffer Objects: yes, max 8 color attachments
  tgt.GpuCapabilities (Info)  Shaders: yes (OpenGL 2.0), GLSL Version 4.20, Shader Model 5.0
  tgt.GpuCapabilitiesWindows (Info)  Graphics Driver Version: 8.17.12.9573
  tgt.GpuCapabilitiesWindows (Info)  Graphics Driver Date: 2012-02-09
  tgt.GpuCapabilitiesWindows (Info)  Graphics Memory Size: 1280 MB
  </code></pre>
  
  <p>My friend's computer:</p>
  
  <pre><code> tgt.GpuCapabilities (Info)  OS version: Windows 7 Service Pack 1 (build 7601)
  tgt.GpuCapabilities (Info)  OpenGL Version: 4.2.11566 Compatibility Profile Context
  tgt.GpuCapabilities (Info)  OpenGL Renderer: AMD Radeon HD 6620G
  tgt.GpuCapabilities (Info)  GPU Vendor: ATI Technologies Inc. (ATI)
  tgt.GpuCapabilities (Info)  Texturing: yes, max size: 16384, 3D: yes, max 3D size: 8192
  tgt.GpuCapabilities (Info)  Texture features: 16 units, NPOT, rectangles, compression, 16x anisotropic
  tgt.GpuCapabilities (Info)  Framebuffer Objects: yes, max 8 color attachments
  tgt.GpuCapabilities (Info)  Shaders: yes (OpenGL 2.0), GLSL Version 4.20, Shader Model 5.0
  tgt.GpuCapabilitiesWindows (Info)  Graphics Driver Version: 6.14.10.11566
  tgt.GpuCapabilitiesWindows (Info)  Graphics Driver Date: 2012-03-09
  tgt.GpuCapabilitiesWindows (Info)  Graphics Memory Size: 512 MB
  </code></pre>
  
  <p>I am very curious and I cannot figure it out.Should I do some settings for the graphics card?Could some one tell me how to solve the problem?</p>