Criteria for 36/64-bit 4500MHD PCI bar use in Win7?

webadmin@intel.com — Thu, 21 Apr 2011 15:37:37 GMT

Hi,

I've got an unusual situation where a Dell Inspiron 1440 with 4500MHD/GM45 + T6600-2.2 CPU can setup 36-bit PCI BARs for use in Win7 as described at

http://forum.notebookreview.com/gaming-software-graphics-cards/418851-diy-vidock-experiences-35.html#post6056360

We can see in the link the 4500MHD 256MB prefectable BAR is located at the 12.25GB (36-bit) boundary. THis is great as it allows the 32-bit freed space to be used for an external desktop GPU which doesn't support 36-bit PCI BARs.

However, Dell Latitudes with P8xxx/T9xxx CPUs cannot do this, nor can a 2530P with a 4500MHD/GS45 + SL9400-1.86 CPU. In both cases Win7 moves the BARS back into 32-bit space, presumably because 36-bit is inaccessible. This is explained further at

http://forum.notebookreview.com/gaming-software-graphics-cards/418851-diy-vidock-experiences-227.html#post6949956

I'm wondering if it's the CPU that's preventing this from happening, or something else. PAE/DEP settings in the BCD don't fix the problem. If it's the CPU then,what MSR bit do I need to set to enable 36-bit PCI BAR usage in Win7? I hope the chipset isn't somehow limiting the PCI access to 32-bit only.

: confused :

Any help would be appreciated.

nando

x1 1.0 pci-e ports not running at full 2.5Gbps speed

webadmin@intel.com — Wed, 05 May 2010 20:33:34 GMT

Hi Everyone,

As part of the DIY ViDock project, it has been identified that ICH7/8/9M and HM57 I/O controllers are not running to their advertised 2.5Gbps in either direction. There is somewhere between 15-30% less performance than expected. It is not clear why these port are not seeing full performance. Is the port sharing bandwidth with another port? Is it running only half-duplex? This problem was identified by the following signs:

1. noticably slower performance compared to x1 1.0 set Nvidia MCP79 chipset as shown here.

2. full x1 1.0 speed is possible if the port is manually switched to have a link width of x2 as shown here. That can only apply to odd numbered ports with no device attached to the next sequential port. We are calling this x1E mode "Intel-Enhanced".

Point 2 then raises the question: how can *any* pci-e port be switched to gain full x1 1.0 performance? (2) above restricts the performance benefits to only some setups. I have tried numerous settings by referring to ICH9M I/O datasheet with no success so far.

If this problem cannot be corrected, then I would like to ask Intel to check their advertising of their pci-e ports as the performance is certainly not 2.5Gbps in either direction. There is precious bandwidth that needs to be uncapped.

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Criteria for 36/64-bit 4500MHD PCI bar use in Win7?

x1 1.0 pci-e ports not running at full 2.5Gbps speed