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View Full Version : I have this PCIE setting in my BIOS, but what does it mean?


newls1
03-28-05, 06:34 PM
I have this BIOS option on my MSI NEO4 PLAT SLI board and have no clue what it means. The option is called "MAXIMUM PAYLOAD SIZE" I read in the users manual, and it said nothing about what it does. It is currently set to 4096, that is the highest it can go, and the options are 4096-128........ What does this mean, and where should it be set @? Thank you

jAkUp
03-28-05, 08:49 PM
Yea mine has that also... I dunno what it means either... maybe like AGP aperature size?

newls1
03-29-05, 08:56 PM
Yea mine has that also... I dunno what it means either... maybe like AGP aperature size?

What do you have yours set at?

jAkUp
03-29-05, 09:09 PM
Mine is at 4096 as well

Viral
03-29-05, 09:54 PM
Well, 4GB/s in each direction is the bandwidth in which 16x PCI-E transfers at, so my guess is that it is the transfer speed in MB/s. Best to keep it at 4096MB/s then.

SH64
03-30-05, 12:08 AM
Well, 4GB/s in each direction is the bandwidth in which 16x PCI-E transfers at, so my guess is that it is the transfer speed in MB/s. Best to keep it at 4096MB/s then.

Yep that makes sense . its set to 4096 as defualt for me as well .

ChrisRay
03-30-05, 12:20 AM
This is not texture size So its nothing like AGP apature.. Its a packet size for data streams and PCIE. Setting it lower will degrade performance.

joltcola
04-01-05, 10:46 PM
This is not texture size So its nothing like AGP apature.. Its a packet size for data streams and PCIE. Setting it lower will degrade performance.

Thanks.. i was wondering about that setting.

-- jolt

SH64
04-01-05, 10:52 PM
What about the best PCI-E frequency ?? its set to 100Mhz as default & can go up to 133Mhz ?

Viral
04-01-05, 11:42 PM
Always leave the frequency settings at default.

ChrisRay
04-02-05, 12:02 AM
What about the best PCI-E frequency ?? its set to 100Mhz as default & can go up to 133Mhz ?


Thats no different than AGP frequency. It basically increases the speed of the PCIE Bus. Just another form of OCing that can see some improvements. I would still leave it aone. heh

H-street
04-02-05, 02:29 AM
● Maximum Payload Size: The Max_Payload_Size parameter limits the maximum size of a TLP's (Transaction layer packet) data
payload.


PCI Express x1 Throughput

Test#____Payload Size (bytes)____Throughput (Gbps)
....1...................................64........ .................................1.45
....2...................................128 ......................................1.59
....3...................................256....... ................................1.76
....4.................................. 512.......................................1.84
....5...................................1024...... ...............................1.92
....6...................................2048...... ...............................1.95
....7...................................4096...... ...............................1.95



PCI Express x4 Throughput

Test#____Payload Size (bytes)____Throughput (Gbps)
....1...................................64........ .................................5.76
....2...................................128 ......................................6.39
....3...................................256....... ................................7.04
....4.................................. 512.......................................7.34
....5...................................1024...... ...............................7.59
....6...................................2048...... ...............................7.76
....7...................................4096...... ...............................7.77


here is a very good article on the PCI/PCIe workings that explains more about the TLP..

http://www.plxtech.com/products/pci_express/whitepapers/TechnologyBrief_PCIExpress_Q4-2003.pdf

SH64
04-04-05, 03:34 AM
http://www.plxtech.com/products/pci_express/whitepapers/TechnologyBrief_PCIExpress_Q4-2003.pdf

Thanks , some interesting info in that document .