What were the best LGA 1366 Workstations?

[cbn]

What were the best LGA 1366 Workstations (Tower/Desktop form factor) in terms of performance, reliability and repairability?

So far I have found out the following models were available from Dell, HP, and Lenovo:

Dell Precision T3500 (1P)
Dell Precision T5500 (2P)
Dell Precision T7500 (2P)

HP Z400 (1P)
HP Z600 (2P)
HP Z800 (2P)

Lenovo S20 (1P)
Lenovo D20 (2P)

1P = single processor
2P = dual processors

Here is some research on the Dell Precision T5500 as a baseline:

One form factor with two orientations: Tower and Mini-Tower (Mini-Tower Orientation = 5.25" bays are rotated 90 degrees so they are parallel with the floor when the tower is resting on its side)

Here is front and back picture of T5500 in Tower orientation:

Here is a picture of the motherboard:

And here is picture of the daughterboard (which holds the second CPU and three additional DIMM slots) with and without heatsink fan and RAM mounted:

Maximum RAM: 48GB (with 6 DIMMs populated) or 72GB (with additional 3 DIMMs on daughter board populated)

Bays:

Two internal 3.5" HDD bays
Two external 5.25" optical bays, one of which can accommodate a third HDD in desktop orientation
One external 3.5" flex bay for media card reader or third (SATA) HDD, in mini-tower orientation.

Exapansion slots:

All full length except as noted.
Two PCI-e x16 slots wired as x8 (half length)
Two PCI-e x16 Gen 2 graphics slots up to 150 watts each
One PCI-X 64bit/100MHz slot with support for 3.3v or universal cards (half length)
One PCI 32bit/33Mhz 5V slot (half length in desktop orientation)

Power supply: 875 watt 88% efficiency (80 Plus Silver) (PCIe power connectors: two 6 pin)

Here is a video showing upgrade of RAM, HDDs and Video cards (which involves removal of the daughterboard) for a Tower orientation T5500 : https://www.youtube.com/watch?v=7YfKmMptByU

And a snapshot of the upgrade process midway through:

(Notice daughterboard for 2nd CPU in technicians hands)

 

[cbn]

For the T5500 there were two heatsinks available for the primary CPU:

An Aluminum one (T021F):

(Entry level heatsink)


And one with heatpipes (U016F):

(Performance heatsink)

 

[XavierMace]

Leave it to Dell to use a daughter card rather than just use a dual socket board. LOL.

 

[cbn]

HP Z800:

Picture of Motherboard:

Processors up to 130W

12 DIMM slots for DDR3 ECC Memory (192 GB capacity)

3 External 5.25” Bays
4 Internal 3.5” Bays

2 PCIe x16 Gen2 Slots
2 PCIe x8 Gen2 Slots
1 PCIe x4 Gen2 Slot
1 PCIe x4 Gen1 Slot
1 PCI Slot

6 SATA 3 Gbps
8 Serial Attached SCSI (SAS)

PSU: 850W 85% efficiency or 1100W 89% efficiency

Additional specs here ---> http://www8.hp.com/h20195/v2/getDocument.aspx?docname=c04110962

Videos:

PSU removal (pretty amazing in that it can removed with disconnecting any cables):
https://youtu.be/vLbWZA0L49c?t=63

Workstation Disassembly (needs no tools for removal of the motherboard): https://www.youtube.com/watch?v=lwRDORLALqw

 

[cbn]

HP Z600:

Processors up to 95W

6 DIMM Slots for DDR3 ECC Memory (48GB with 8GB DIMMs)

2 Internal 3.5" bay
2 External 5.25" bays

2 PCIe x 16 Gen 2 slots
1 PCIe x8 (x4 electrical) Gen 1 slot
1 PCIe x8 (x4 electrical) Gen 1 slot
2 PCI Slots

Six SATA 3 Gbps

650W 85% efficient Power supply

More specs here--> http://www8.hp.com/h20195/v2/getDocument.aspx?docname=c04110961

 

[sm625]

The T3500 is better. There are greater quantities available, which makes for more easily replaceable parts. The dual cpu thing is kind of overkill. If you really truly need that many cores then you're probably going to have someone else willing to foot the bill for new hardware anyway.

 

[cbn]

T3500:

Processors up to 130 watts are supported
X58 chipset

6 DIMM slots for up to 24GB Memory (ECC and Non-ECC)

Bays:

Two internal 3.5" HDD bays

Two external 5.25" optical bays
One external 3.5" flex bay for media card reader or third (SATA) HDD

Slots:

All full length except as noted.
Two PCI-e x8 slot wired as x4 (one half-length)
Two PCI-e x16 Gen 2 graphics slots
Two PCI slots (both half length)

525W 88% efficient 80 plus silver PSU
525W PSU
(PCIe power connectors: one 6 pin)

Dell Precision T3500 Workstation manual --> http://i.dell.com/sites/doccontent/...Documents/precision-t3500-technical-guide.pdf

 

[cbn]

The T3500 is better. There are greater quantities available, which makes for more easily replaceable parts.

Right now the price difference for power supplies is $7 more for the T5500 (875W) vs. T3500 (525W) going by current ebay "buy it now" listings. Keep in mind though the T5500 875W came in 80 plus Silver and the T3500 had two 525W available (one 80 plus Silver and one not listed with certification). So for that part (at least) the difference is not much.

P.S. At some point I will start comparing the prices of other PSUs, upgrade heatsinks (eg, U016F from post #2 currently starts at $15 shipped), ECC RDIMMs, ECC UDIMMs, and anything else you or other folks are interested.

The dual cpu thing is kind of overkill. If you really truly need that many cores then you're probably going to have someone else willing to foot the bill for new hardware anyway.

Some current ebay "buy it now" listing prices on LGA 1366 processors:

45nm quad cores:

X5570 4C/8T 8MB cache 2.93 Ghz/3.33 Ghz, 95W: starts at $20 shipped
X5560 4C/8T 8MB cache 2.80 Ghz/3.2 Ghz, 95W: starts at $19 shipped
X5550 4C/8T 8MB cache 2.66 Ghz/3.06 Ghz 95W: starts at $20 shipped
W5590 4C/8T 8MB cache, 3.33 GHz/3.6 Ghz 130W: starts at $43 shipped
W5580 4C/8T 8MB cache, 3.2 Ghz/3.46 Ghz 130W: starts at $30 shipped

32nm quad cores:

X5687 4C/8T 12MB cache 3.6 Ghz/3.86 Ghz turbo, 130W: starts at $95 shipped
X5677 4C/8T 12MB cache 3.46 GHz/3.73 Ghz turbo, 130W: starts at $65 shipped
X5672 4C/8T 12MB cache 3.2 Ghz/3.6 Ghz turbo, 95W: starts at $55 shipped
X5647 4C/8T 12MB cache 2.93 Ghz/3.2 Ghz turbo 130W: starts $40 shipped.

32nm Hexcores:

X5690 6C/12T, 12MB cache, 3.46 Ghz/3.73 Ghz turbo, 130W TDP starts at $222 shipped
X5680 6C/12T, 12MB cache, 3.33 Ghz/3.6 Ghz turbo, 130W TDP starts at $150 shipped
X5675 6C/12T, 12MB cache, 3.06 Ghz/3,46 Ghz turbo, 95W TDP starts at $120 shipped
X5670 6C/12T, 12MB cache, 2.92 Ghz/3.33 Ghz turbo, 95W TDP starts at $99 shipped
X5660 6C/12T, 12MB cache, 2.8 Ghz/3.2Ghz turbo, 95W TDP starts at $80 shipped
X5650 6C/12T, 12MB cache, 2.66 Ghz/3.06Ghz turbo, 95W TDP starts at $81 shipped

If the 2P Workstation and associated parts don't end up being that much more expensive it might be worth looking into two lesser processors vs. using one more expensive processor.

Also another thing to consider: a 2P workstation can be run with one processor.

 

[cbn]

Some passmark comparisons:

i7 4790K ($339, 88W): 11237 CPU Marks http://www.cpubenchmark.net/cpu.php?cpu=Intel+Core+i7-4790K+@+4.00GHz
i7 4790 ($305, 84W): 10074 CPu marks http://www.cpubenchmark.net/cpu.php?cpu=Intel+Core+i7-4790+@+3.60GHz
i7 2600 ($150 on ebay "buy it now" listings, 95W): 8269 CPU marks http://www.cpubenchmark.net/cpu.php?cpu=Intel+Core+i7-2600+@+3.40GHz
i5 4670 ($224, 84W): 7407 CPU marks http://www.cpubenchmark.net/cpu.php?cpu=Intel+Core+i5-4670+@+3.40GHz

Westmere:

6C/12T overclocked to 4.2 Ghz: 11130 CPU marks http://forums.anandtech.com/showpost.php?p=37468356&postcount=50
6C/12T overclocked to 4.73 Ghz: 11990 CPU marks http://forums.anandtech.com/showpost.php?p=37468393&postcount=51

Dual X5677 ($130 for 2 processors, 260W): 11815 CPU marks http://www.cpubenchmark.net/cpu.php?cpu=Intel+Xeon+X5677+@+3.47GHz&id=1310&cpuCount=2
Dual X5660 ($160 for 2 processors, 190W): 11821 CPU marks http://www.cpubenchmark.net/cpu.php?cpu=Intel+Xeon+X5660+@+2.80GHz&cpuCount=2

Nehalem:

Dual W5590 ($86 for 2 processors, 260W): 10646 CPU marks http://www.cpubenchmark.net/cpu.php?cpu=Intel+Xeon+W5590+@+3.33GHz&cpuCount=2
Dual X5570 ($40 for 2 processors, 190W): 9696 CPU marks http://www.cpubenchmark.net/cpu.php?cpu=Intel+Xeon+X5570+@+2.93GHz&cpuCount=2

Some observations:

1.) Dual mid level Westmere Xeons are competitive with a single overclocked Xeon hexcore. Performance per watt should be better too, although single thread performance will be worse.

2.) If a person has a 2P motherboard that can use 130W processors, running dual X5677 32nm quad cores will be $30 lower cost than dual X5660 32nm hexcores. Single thread performance will also be better on the X5677 quad cores since the base clocks (3.46 Ghz vs. 2.8 Ghz) and turbo (3.73 Ghz vs. 3.2 Ghz) are higher than X5660. However, multi-thread performance per watt will be lower.

3.) Dual X5570 Nehalem quad cores are cheap and have decent MT performance. They would also work on any 2P motherboard since they are only 95W CPUs.

4.) The Dual LGA 1366 processors listed in this post are much better than a i7 2600 in terms of multi-threaded performance per dollar. Keep in mind though, LGA 1155 pre-built desktops cost less money (and use less power)....but the LGA 1366 Workstations have more features (higher memory capacity, ECC RAM, more SATA ports, Power supply with higher wattage, dual PCIe x16 Gen 2 slots, etc.)
__________________

 

[Blue_Max]

I have a special love for this thread. Many of these workstations can be picked up CHEAP and can be upgraded with cheap but great Xeons.

Missed my chance to get an empty one for $50 to stick my old i7-920 in, but I'd spend more to grab one with dual capability and upgrade it in steps.

Next time I see the right machine (one listed here) I'll have to jump on it immediately!

 

[cbn]

Dell T7500:

(Notice the above daughter board has six DIMMs slots rather than the three DIMM slots as found on the T5500 daughter board)

Maxium RAM: 96 GB, 192 GB when daughter board is populated

Bays

Four internal 3.5" HDD bays
Three external 5.25" optical bays, one of which can accommodate a fifth HDD
One external 3.5" flex bay for media card reader

Slots

All full length except as noted.
One PCI-e x16 Gen 2 wired as x4
Two PCI-e x16 Gen 2 slots wired as x8 (one is half length)
Two PCI-e x16 Gen 2 graphics slots
One PCI-X 64bit/100MHz slot with support for 3.3v or universal cards
One PCI 32bit/33Mhz 5V slot

Power supply: 1100 watts 88% (80 Plus Silver Certified) efficient Power Factor Correcting (PFC) power supply (PCIe power connectors: two 6 pin and one 8 pin)

 

[cbn]

HP Z400:

Processors up to 130W supported.
X58 chipset

6-DIMM slots for DDR3 ECC memory

3 External 5.25” Bays

2 Internal 3.5” Bays

2 PCIe x16 Gen2 Slots
1 PCIe x4 Gen2 (x8 mechanical, open ended)
1 PCIe x4 Gen1 (x8 mechanical, open ended)
2 PCI Slots

475W, 85% efficient Power Supply (made by Delta)
600W, 80% efficient Power supply (optional) (made by Delta)

Additional specs here--> http://www8.hp.com/h20195/v2/getDocument.aspx?docname=c04110960

 

[MongGrel]

http://www.newegg.com/Product/Product.aspx?Item=N82E16813188070

Built with a good tower back then case I imagine.

Or if ya want to spend the money to do one these days.

 

[MongGrel]

I let one slide buy a year ago I guess.

 

[cbn]

Lenovo S20:

Processors up to 130W supported
X58 chipset

Six DIMM slots (Some Lenovo documentation lists 24GB max, while other documentation lists max RAM at 48 GB)

Bays:
Three 3.5-inch slim internal hidden bay (HDD)
One 3.5-inch slim external accessible bay (FDD or card reader)
Two 5.25-inch external half-high bay (optical drives)

Slot 1: PCIe 2.0 x16
Slot 2: PCIe 2.0 x4 (x16 mechanical)
Slot 3: PCIe 2.0 x16
Slot 4: PCIe x1
Slot 5: PCI

5 SATA, 1 eSATA

Power supply: 625W 80 plus Bronze with 120mm bottom-mounted variable speed fan. (PCIe power connectors: two 6 pin and one 8 pin)

Additional specs ---> http://www.lenovo.com/shop/americas/content/pdf/system_data/s20_tech_specs.pdf, http://support.lenovo.com/us/en/documents/pd005642, http://www.lenovo.com/shop/americas...tion/WW_ThinkStation-S20-D20_FA_low_Mar20.pdf

 

[coit]

I pick up a T7500 tomorrow.
2xX5660
Quadro 5000
24GB RAM
I will use it as my desktop and try fitting usb3 and pcie ssd cards.
Friends reckon Im mad but workstations have always had a fascination for me.

 

[Rakehellion]

How do you overclock a Xeon?

 

[Burpo]

You can't on any of the branded systems above..

BUT, if you have a decent motherboard..

 

[cbn]

Lenovo S20:

Processors up to 130W supported
X58 chipset

Six DIMM slots (Some Lenovo documentation lists 24GB max, while other documentation lists max RAM at 48 GB)

Bays:
Three 3.5-inch slim internal hidden bay (HDD)
One 3.5-inch slim external accessible bay (FDD or card reader)
Two 5.25-inch external half-high bay (optical drives)

Slot 1: PCIe 2.0 x16
Slot 2: PCIe 2.0 x4 (x16 mechanical)
Slot 3: PCIe 2.0 x16
Slot 4: PCIe x1
Slot 5: PCI

5 SATA, 1 eSATA

Power supply: 625W 80 plus Bronze with 120mm bottom-mounted variable speed fan. (PCIe power connectors: two 6 pin and one 8 pin)

Additional specs ---> http://www.lenovo.com/shop/americas/content/pdf/system_data/s20_tech_specs.pdf, http://support.lenovo.com/us/en/documents/pd005642, http://www.lenovo.com/shop/americas...tion/WW_ThinkStation-S20-D20_FA_low_Mar20.pdf

On this S20 if you look at the third and fourth pictures you will notice too different heatsinks (A larger higher performance one in the third picure and a smaller one in the fourth picture). I found out the Dell T3500 has two heatsink options as well:

http://en.community.dell.com/support-forums/desktop/f/3514/t/19499180 (The same two heatsink options used by the Dell T5500 as described in post #2 of this thread)

The HP Z400, I believe, only has one heatsink though....a high performance one (that covers both low and high TDP processors). EDIT: The HP Z400 also has a liquid cooler, but it is true that there is only one air cooler to cover both high and low TDP processors.

 

[cbn]

Some current ebay "buy it now" listing prices on LGA 1366 processors:

45nm quad cores:

X5570 4C/8T 8MB cache 2.93 Ghz/3.33 Ghz, 95W: starts at $20 shipped
X5560 4C/8T 8MB cache 2.80 Ghz/3.2 Ghz, 95W: starts at $19 shipped
X5550 4C/8T 8MB cache 2.66 Ghz/3.06 Ghz 95W: starts at $20 shipped
W5590 4C/8T 8MB cache, 3.33 GHz/3.6 Ghz 130W: starts at $43 shipped
W5580 4C/8T 8MB cache, 3.2 Ghz/3.46 Ghz 130W: starts at $30 shipped

32nm quad cores:

X5687 4C/8T 12MB cache 3.6 Ghz/3.86 Ghz turbo, 130W: starts at $95 shipped
X5677 4C/8T 12MB cache 3.46 GHz/3.73 Ghz turbo, 130W: starts at $65 shipped
X5672 4C/8T 12MB cache 3.2 Ghz/3.6 Ghz turbo, 95W: starts at $55 shipped
X5647 4C/8T 12MB cache 2.93 Ghz/3.2 Ghz turbo 130W: starts $40 shipped.

32nm Hexcores:

X5690 6C/12T, 12MB cache, 3.46 Ghz/3.73 Ghz turbo, 130W TDP starts at $222 shipped
X5680 6C/12T, 12MB cache, 3.33 Ghz/3.6 Ghz turbo, 130W TDP starts at $150 shipped
X5675 6C/12T, 12MB cache, 3.06 Ghz/3,46 Ghz turbo, 95W TDP starts at $120 shipped
X5670 6C/12T, 12MB cache, 2.92 Ghz/3.33 Ghz turbo, 95W TDP starts at $99 shipped
X5660 6C/12T, 12MB cache, 2.8 Ghz/3.2Ghz turbo, 95W TDP starts at $80 shipped
X5650 6C/12T, 12MB cache, 2.66 Ghz/3.06Ghz turbo, 95W TDP starts at $81 shipped

If the 2P Workstation and associated parts don't end up being that much more expensive it might be worth looking into two lesser processors vs. using one more expensive processor.

Also another thing to consider: a 2P workstation can be run with one processor.

In comparison to the above prices (taken June 9th, 2015), here are the prices I found on ebay "Buy it now" listings yesterday:

45nm quad cores:

X5570 4C/8T 8MB cache 2.93 Ghz/3.33 Ghz, 95W: starts at $14 shipped
X5560 4C/8T 8MB cache 2.80 Ghz/3.2 Ghz, 95W: starts at $9 shipped
X5550 4C/8T 8MB cache 2.66 Ghz/3.06 Ghz 95W: starts at $7 (OBO) shipped
W5590 4C/8T 8MB cache, 3.33 GHz/3.6 Ghz 130W: starts at $36 shipped
W5580 4C/8T 8MB cache, 3.2 Ghz/3.46 Ghz 130W: starts at $30 (OBO) shipped

32nm quad cores:

X5687 4C/8T 12MB cache 3.6 Ghz/3.86 Ghz turbo, 130W: starts at $66 shipped
X5677 4C/8T 12MB cache 3.46 GHz/3.73 Ghz turbo, 130W: starts at $45 shipped
X5672 4C/8T 12MB cache 3.2 Ghz/3.6 Ghz turbo, 95W: starts at $44 shipped
X5647 4C/8T 12MB cache 2.93 Ghz/3.2 Ghz turbo 130W: starts $19 shipped.

32nm Hexcores:

X5690 6C/12T, 12MB cache, 3.46 Ghz/3.73 Ghz turbo, 130W TDP starts at $165 shipped
X5680 6C/12T, 12MB cache, 3.33 Ghz/3.6 Ghz turbo, 130W TDP starts at $107 shipped
X5675 6C/12T, 12MB cache, 3.06 Ghz/3,46 Ghz turbo, 95W TDP starts at $64 shipped
X5670 6C/12T, 12MB cache, 2.92 Ghz/3.33 Ghz turbo, 95W TDP starts at $50 (OBO) shipped
X5660 6C/12T, 12MB cache, 2.8 Ghz/3.2Ghz turbo, 95W TDP starts at $41 shipped
X5650 6C/12T, 12MB cache, 2.66 Ghz/3.06Ghz turbo, 95W TDP starts at $28.50 shipped

 

[cbn]

Some current 1P Xeon pricing to add to the 2P Xeon pricing in the above post:

W3690, 6C/12T 12MB cache 3.46 Ghz/3.73 Ghz, 1333 Mem controller, 130W, starts $144 shipped
W3680, 6C/12T 12MB cache 3.33 Ghz/3.6 Ghz, 1333 Mem controller, 130W, starts $115 (OBO) shipped (although I did see this one recently for $89 shipped)
W3670, 6C/12T 12MB cache, 3.2 Ghz/3.46 Ghz, 1066 Mem controller, 130W: starts at $50 (OBO) shipped.
W3580 4C/8T 8MB cache, 3.33 Ghz/3.6 Ghz, 1333 Mem controller, 130W, starts $45 (OBO) shipped (from China).
W3570 4C/8T 8MB cache, 3.2 Ghz/3.46 Ghz, 1333 Mem controller, 130W: starts $22 (OBO) shipped
W3565 4C/8T 8MB cache, 3.2 Ghz/3.46 Ghz, 1066 Mem controller, 130W: starts $15 (OBO) shipped
W3550 4C/8T 8MB cache, 3.06 Ghz/3.33 Ghz, 1066 Mem controller, 130W starts $10.50 (OBO) shipped
W3540 4C/8T 8MB cache, 2.93 Ghz/3.20 Ghz, 1066 Mem controller, 130W starts $7 shipped
W3530 4C/8T 8MB cache, 2.80 Ghz/3.06 Ghz, 1066 Mem controller, 130W starts $5 shipped

 

[cbn]

Comparing W3670 and X5670:

http://www.cpu-world.com/Compare/854/Intel_Xeon_W3670_vs_Intel_Xeon_X5670.html

And W3670 vs. X5675:

http://www.cpu-world.com/Compare/859/Intel_Xeon_W3670_vs_Intel_Xeon_X5675.html

Besides W3670 having a higher TDP (130W vs. 95W) and a lower spec memory controller (triple channel DDR3 1066 vs. triple channel DDR3 1333) I noticed it also has a lower maximum operating temperature (67.9C vs. 81.3C). This means the fan will kick in a lot sooner than on the two X56xx processors.

With that mentioned, I do have a some DDR3 1066 lying around that needs to be used.....so I might buy W3670 over X5670 or X5675.

 

[cbn]

X5660 (2.8GHz/3.2 GHz 95W hexcore) dropped to $32.25 shipped in one ebay buy it now listing. There is also another listing for the same processor at $32.99 free shipping. The first listing has 105 processors available and the second one has 35 processors available.

So a sudden influx of server pulls can cause a fairly strong decrease in pricing.

 

[Riok]

Hello, here are some firestrike scores comparing the xeon to more modern CPU. The goal is to see if it's a good cpu for gaming.

GTX 980
Intel Core i3 6320 + NVIDIA GeForce GTX 980 = Firestrike 10000
Intel Xeon Processor X5680 + NVIDIA GeForce GTX 980 = Firestrike 11000

GTX 1060
Intel Core i3 6320 + NVIDIA GeForce GTX 1060 = Firestrike 10000
Intel Core i7-920 Processor STOCK + NVIDIA GeForce GTX 1060 = Firestrike 12000
Intel Core i7-7700 + NVIDIA GeForce GTX 1060 = Firestrike 12000
Intel Xeon Processor X5680 + NVIDIA GeForce GTX 1060 = Firestrike 12000

GTX 1070
Intel Xeon Processor W3540 STOCK + NVIDIA GeForce GTX 1070 = Firestrike 12000
Intel Core i3 6100 + NVIDIA GeForce GTX 1070 = Firestrike 13000
Intel core i7 920 + NVIDIA GeForce GTX 1070 = Firestrike 14000
Intel Core i5 6400 + NVIDIA GeForce GTX 1070 = Firestrike 14000
Intel Core i7-7700 + NVIDIA GeForce GTX 1070 = Firestrike 16000
Intel Xeon Processor X5680 + NVIDIA GeForce GTX 1070 = Firestrike 16000

GTX 1080
Intel Core i3 6320 + NVIDIA GeForce GTX 1080 = Firestrike 12000
Intel Core i5 6400 + NVIDIA GeForce GTX 1080 = Firestrike 18000
Intel Core i7-7700 + NVIDIA GeForce GTX 1080 = Firestrike 18000
Intel Xeon Processor X5680 + NVIDIA GeForce GTX 1080 = Firestrike 17000

One can see it's useless with a middle end card but gets usefull to unleash the power of the bigger cards. Today the i7-7700 cost 240€ and you can get a X5650 for 35€ or an X5680 for 50€.

 

[Riok]

Some Q&A about the HP Z400:

1) Is it possible to upgrade to a x5670 processor ?
Yes with a bios upgrade.

2) Is it possible to overclock ?
Yes. I like that introduction video about overclocking:
Overclocking a Xeon x5670 CPU to 4GHz

3) Is it possible to plug a new CPU Fan ?
" The stock cooler in the HP Z400, supplied by Cooler Master, is quite good if you change the fan, though the proprietary 5 pin connector might require some plastic snipping to get a 4 pin fan hooked up to the top 4 pins."

4) Is it possible to plug 2 120mm fans and have bios fan control ?
There is a very good article from Matrox on HP forum about the Z400 fan control:
Z400 cooling strategy 'revealed'

5) Is it possible to plug a modern 8pin GFX card ?
Yes, even HP provides an official 6pin to 8pin adapter. I don't know the reference of an alternative adapter.

6) Will it fit ?
The z400 Accepts 4.4 H x 9.50 L inch cards.
The 970 strix is 5.5 x 11 inch.
So... it seems not ?!

7) Is it possible to replace the PSU with a standard one ?
That needs some wiring, some plans are available. Many adapters exist for the z420 to power it with a standard PSU but I don't think the z400 can use them.

8) What kind of RAM is needed for upgrade ?
ECC DDR3 unbuffered


I don't have a Z400 at the moment to test that so any comments from users are welcome.