Advise on a new processor

[captdini 3]

Folks,Could I get some thoughts on a new processor to buy.I have the option of picking up a machine with an i7 980X (alienware) or should I wait for the new Sandy Bridge CPU's coming out next year ?Thanks,Dinshaw.

[Guest chris493]

Alienware is a waste of money. Build a system yourself. It isn't all that hard and we are always here to help you. It will save yourself a LOT of money and you get what YOU want.

[Guest jahman]

I you are currently simming OK, I would wait, as NextGen microarchitectures and die shrinks historically bring around a 15% improvement in performance (equivalent to say a +500 MHz OC).If you have money to burn, go for the 980X now, get the Sandy Bridge next year. Even with less of a budget you could get the 980X now, then sell your PC on eBay and use the proceeds towards Sandy Bridge.The interesting part about Sandy Bridge to me is the Socket 2011 for 2x QPI allowing for 4 concurent banks of RAM, (thus increasing memory bandwidth by 33% at the same memory clock speed?) for a total RAM bandwidth of 51.2 GBy, and with a whopping 40 PCIe v. 3 lanes (and PCIe v. 3 is 2x the speed of PCIe v. 2, so we would be looking at the equivalent of 80 PCIe lanes (recall one of the bottlenecks in FSX with lots of autogen is PCIe bandwidth, but then again it seems for PCIe 3 we will have to wait for NextGen video cards in late 2011... but that's when Socket 2011 will be released!)See: 8-Core Sandy Bridge -EX and -EP Server slated for release in 4Q2011 and 3Q2011, respectively.A final alternative is to wait for MS Flight and see what Flight's hardware requirements are: If Flight is more balanced in its software architecture and better at using hardware (DX11, Shader 4, multiple CPUs, Multiple GPU's) as we all expect, then we won't need that much computing power in the first place! Note it is likely for Flight to be released prior to the 2011 Holiday Season, together with the Sandy Bridge -EX and -EP and PCIe v. 3 video cards!Not sure how much this helps you decide though :-)Cheers.- jahman.

[dazz 69]

Socket 2011 for 2x QPI allowing for 4 concurent banks of RAM, (thus increasing memory bandwidth by 33% at the same memory clock speed?) for a total RAM bandwidth of 51.2 GBy

The QPI links have nothing to do with memory banks, # of channels, bandwidth. They never did, even in x58. The QPI link is just that, a link, a very fast one to interconect parts of the architecture that are not integrated in the CPU chip and need a high data transfer rate. In x58 the QPI link connected the CPU with the northbridge (IOH) where the PCIe controller was. In the 2010 socket architecture the 2 QPI links are there just to interconnect sockets for multi socket boards (servers that need to execute many tasks simultaneously) nothing to do with memory anyway. There's no need for a QPI link anymore since the northbridge is gone (2011 has on-die PCIe controller) As for the 4 channels, that means that with memos at 800MHz (DDR3 1600) you have a MAXIMUM of 4 x 10.6 GB/s = 42.4 GB/s of memory bandwidth available.... good luck at finding a set of ram sticks capable of doing 20 GB/s and an application that needs that much bandwidth to even notice the difference (the difference with nehalems will come from the better clock for clock productivity, and higher OC)

I recall one of the bottlenecks in FSX with lots of autogen is PCIe bandwidth

where did you get this idea? got a link please? no offense but it makes no sense to me

[Guest jahman]

The QPI links have nothing to do with memory banks, # of channels, bandwidth. They never did, even in x58. The QPI link is just that, a link, a very fast one to interconect parts of the architecture that are not integrated in the CPU chip and need a high data transfer rate. In x58 the QPI link connected the CPU with the northbridge (IOH) where the PCIe controller was. In the 2010 socket architecture the 2 QPI links are there just to interconnect sockets for multi socket boards (servers that need to execute many tasks simultaneously) nothing to do with memory anyway. There's no need for a QPI link anymore since the northbridge is gone (2011 has on-die PCIe controller)

Indeed! Many thanks for the heads-up! I had thought QPI also interfaced the RAM...

As for the 4 channels, that means that with memos at 800MHz (DDR3 1600) you have a MAXIMUM of 4 x 10.6 GB/s = 42.4 GB/s of memory bandwidth available.... good luck at finding a set of ram sticks capable of doing 20 GB/s and an application that needs that much bandwidth to even notice the difference (the difference with nehalems will come from the better clock for clock productivity, and higher OC)

Sandy Bridge Socket 2011 indeed does have peak RAM bandwidth of 51.2 GBy/Sec.

where did you get this idea? got a link please? no offense but it makes no sense to me.

I get my ideas from Phil Taylor: "Holy Autogen Batman! Yes, this is why autogen brings the system to its knees!" :-)Cheers,- jahman.

[dazz 69]

Sandy Bridge Socket 2011 indeed does have peak RAM bandwidth of <a href='http://pc.watch.impress.co.jp/video/pcw/docs/360/112/6.pdf' class='bbc_url' title='External link' rel='nofollow external'>51.2 GBy/Sec</a>.<br /> <br /><br /><br /><br />

My bad, 51.2 is correct, 42.4 would be for DDR3-1333Bus width = 64 bits = 8 bytesChannel speed @ 1600MHz = 1600M * 8 = 12.8Gb/s2011: 4 channels x 12.8 = 51.2Gb/sBut still, there's no memory capable of that, not even close.

I get my ideas from Phil Taylor: "<a href='http://blogs.msdn.com/b/ptaylor/archive/2008/04/17/back-of-the-envelope.aspx' class='bbc_url' title='External link' rel='nofollow external'>Holy <b>Autogen</b> Batman! Yes, this is why autogen brings the system to its knees!</a>" :-)<br /><br />Cheers,<br /><br />- jahman.<br />

Very interesting read. thanks for the link. That could make PCIe 3 a great thing to have for FSX then. I wonder how autogen doesn't really effect performance that much for me, but it could well be all the rest of stuff also clogging the PCIe 2.But then again, if the bottleneck is the PCIe BW, shouldn't it render CPU OCing useless?

[cmeeks 8]

I believe socket 1356 is the official replacement for 1366 - both are enthusiast level desktop CPUs. Socket 2011 is server which means it will probably be tons more expensive and won't necessarily be geared towards gaming.Sandy Bridge on Wikipedia Just reading some of the advantages here makes me think I really ought to wait for 1356... I've been pretty set on the i7-2600k.On a side note, if you fly using satellite imagery you don't even have to worry about Autogen

[dazz 69]

I believe socket 1356 is the official replacement for 1366 - both are enthusiast level desktop CPUs. Socket 2011 is server which means it will probably be tons more expensive and won't necessarily be geared towards gaming.Sandy Bridge on Wikipedia Just reading some of the advantages here makes me think I really ought to wait for 1356... I've been pretty set on the i7-2600k.On a side note, if you fly using satellite imagery you don't even have to worry about Autogen

Well, some say there there will be not such thing as a 1356 socket, but who knows. It's far too soon to knowThere's also been a rumour that a new z68 chipset for 1155 will allow non K CPU to overclock (probably just that, a rumor)EDIT: I found this article too http://www.anandtech...wins-in-a-row/3where they say that socket 1155 will sport PCIe 2.0 lanes @ 5GT/sec which is suppose to be twice as fast as current intel chips. Would that alone overcome the PCIe BW bottleneck or will PCIe 3.0 be needed? I have no idea, time will tell

[captdini 3]

Thanks a lot guys for your advise. I do admit, a lot of it went over my head, but I think I am going to stick around with my current machine for a while and wait and see what performance the new processors are going to churn out.Once again thanks Chris, Jahman and Dario for all your help.Dinshaw.