B75 and Z77 mobos findings update
Posted: Tue Mar 12, 2013 5:25 am
well, together a Gearslutz user I'm tightening the circle of candidates
for a new Scope system to try.
Looking also to manuals of different brands Z77 and B75 motheboard models we have found interesting things to evaluate.
[edit]
MSI B75-G43 has in its BIOS the settings for PCI IRQs routing and the PCI Latency Timer as on older motherboards.
(and I didn't found a scheme which indicates that legacy PCI slots are shared with other busses or devices.)
Is it a good thing for you too?
Consider that that instead that in ASrock and Gigabytes B75 mobos manuals I didn't find at all these parameters in their bios!
The Gigabyte model I looked is the GA-P75-D3 (the same tried here by Strattosphere):
its block diagram shows legacy PCI slots are separated from all else, but anyway
he had problems with three Pulsar 2 and a Yamaha in the 4th slot.
[added]
I found only a mysterious parameter: PCI ROM Priority.
The manual says: "Allows you to determine which Option ROM to launch. Options are Legacy ROM and EFI Compatible
ROM. (Default: EFI Compatible ROM)"
But I don't know at all what this means or does.
[edit]
On ASUS P8B75-V the IRQ assignaments paragraph confirms that legacy PCI slots are shared with PCIexpress and audiocard (I guess it from the code)... while SATA controller are separated, not shared with them.
[edit]
On the ASUS P8Z77-V instead the SATA controllers (as chipset as Asmedia) are shared with one PCIe x1 slot not with legacy PCI slots,
but these ones are indeed shared with the other PCIexpress x16 slots!
The first PCI is sharing also with a USB2 and a USB3 controller.
Anyway what makes me wonder a bit is reading the manual of the MSI Z77A-G43 (the one tried here by Braincell), because it seems to be the same manual (same sign?) of the B75A-G43 with just the Z77 adds (that I list later).
So, even on the Z77A-G43 you can find the part with the PCI IRQs sharings and the PCI Latency Timer!!
How could it possible if Z77 hasn't native support for legacy PCI and use the Asmedia 1083 for the bridge to PCIe?
Could be the different "implementation" made by MSI that GaryB talked/conjectured
in the other thread?
MSI B75A-G43 and Z77A-G43 mobos: they seem to be the same base plates: almost identical design and number of PCI slots, with Z77 having added the Asmedia 1083, the improve of USB ports and having 2 SATA3 6gb ports instead of the one only present on B75 model.
The MSI B75-G43 is a good candidate for me to try at this point.
If it works fine I can eventually consider a SATA3 PCIe controller for more 6gb ports,
but I don't know if they can works fine or eat too much PCIe bandwith having a HD7850 graphics card.
for a new Scope system to try.
Looking also to manuals of different brands Z77 and B75 motheboard models we have found interesting things to evaluate.
[edit]
MSI B75-G43 has in its BIOS the settings for PCI IRQs routing and the PCI Latency Timer as on older motherboards.
(and I didn't found a scheme which indicates that legacy PCI slots are shared with other busses or devices.)
Is it a good thing for you too?
Consider that that instead that in ASrock and Gigabytes B75 mobos manuals I didn't find at all these parameters in their bios!
The Gigabyte model I looked is the GA-P75-D3 (the same tried here by Strattosphere):
its block diagram shows legacy PCI slots are separated from all else, but anyway
he had problems with three Pulsar 2 and a Yamaha in the 4th slot.
[added]
I found only a mysterious parameter: PCI ROM Priority.
The manual says: "Allows you to determine which Option ROM to launch. Options are Legacy ROM and EFI Compatible
ROM. (Default: EFI Compatible ROM)"
But I don't know at all what this means or does.
[edit]
On ASUS P8B75-V the IRQ assignaments paragraph confirms that legacy PCI slots are shared with PCIexpress and audiocard (I guess it from the code)... while SATA controller are separated, not shared with them.
[edit]
On the ASUS P8Z77-V instead the SATA controllers (as chipset as Asmedia) are shared with one PCIe x1 slot not with legacy PCI slots,
but these ones are indeed shared with the other PCIexpress x16 slots!
The first PCI is sharing also with a USB2 and a USB3 controller.
Anyway what makes me wonder a bit is reading the manual of the MSI Z77A-G43 (the one tried here by Braincell), because it seems to be the same manual (same sign?) of the B75A-G43 with just the Z77 adds (that I list later).
So, even on the Z77A-G43 you can find the part with the PCI IRQs sharings and the PCI Latency Timer!!
How could it possible if Z77 hasn't native support for legacy PCI and use the Asmedia 1083 for the bridge to PCIe?
Could be the different "implementation" made by MSI that GaryB talked/conjectured
in the other thread?
MSI B75A-G43 and Z77A-G43 mobos: they seem to be the same base plates: almost identical design and number of PCI slots, with Z77 having added the Asmedia 1083, the improve of USB ports and having 2 SATA3 6gb ports instead of the one only present on B75 model.
The MSI B75-G43 is a good candidate for me to try at this point.
If it works fine I can eventually consider a SATA3 PCIe controller for more 6gb ports,
but I don't know if they can works fine or eat too much PCIe bandwith having a HD7850 graphics card.