Which machine has more SATA connectors and more space room for extra hard drives 3.5 Inches

[mgbsher]

Hi,

I would like to build a small home lab, and now I am building my 1st machine.

I want to know which machine has more SATA connectors and more space room for extra hard drives 3.5 Inches?

I am comparing for the Z series, but I found too many models and I can not pick a one as there are z4xx, z6xx, and z8xx.

These xx means (00, 20, and 40) for each model of course of them like z400, z420, z440 and the same for the rest of 6 and 8.

So I did searched the guide but can not find the exact number of SATA connectors for each model to compare and choose the model that its mother board has the extra connectors.

Also, regarding the space inside the machine itself, which one has  the most extra wide space so I can add extra hard drives?

I want to add 10 hard drives at least as I want to have a file storage and backup server or NAS (Network Attached Storage), and a virtualization environment for my studying.

So, please may you just tell me the answer for these questions to pick the right one?

Or I need a whole different machine?

Thanks

[NonSequitur777 · Accepted solution]

@mgbsher,

Welcome to our HP Community forum!

You're asking a great question -HP's Z-series workstations are indeed solid and affordable choices for a home lab, but they do differ significantly in terms of SATA ports and internal drive bay capacity. Here's a breakdown to help you choose:

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Summary of Drive Support Across Z-Series Models:

Model Max SATA Ports 3.5" Bays Max Drive Support

Z400	4 (SATA II)	2	4–6 drives
Z420	6 (SATA II/III)	2–3	6–8 drives
Z440	6 (SATA III)	3	6–10 drives
Z600	4 (SATA II)	2	4–6 drives
Z620	6 (SATA II/III)	3	6–8 drives
Z640	6 (SATA III)	3	6–10 drives
Z800	6 (SATA II)	3–4	6–8 drives
Z820	6 (SATA II/III)	4	6–10+ drives
Z840	6 (SATA III)	4–6	Up to 12+ drives

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Key Considerations for Your Use Case (10+ Drives):

1. Best for Expandability:

   
   ✅Z840 is your top pick — it has:

   • Roomiest chassis (6 internal 3.5" bays + optional cages)

   • Dual CPU support (great for virtualization)

   • 6 native SATA III ports

   • Multiple PCIe slots for RAID/SATA/SAS expansion cards

2. Next Best Options:

   • Z820: Similar to Z840, just older CPUs.

   • Z640/Z440: Smaller but still good expandability; will need a SATA controller to hit 10 drives.

3. Upgrade Path:
   If any Z-series lacks enough SATA ports, you can add:

   • A PCIe SATA controller (like an LSI HBA or Marvell card)

   • Or use USB-to-SATA adapters for lower-performance drives.

---

Recommendation:

• Go with an HP Z840 for your NAS + virtualization goals. It offers the best mix of space, power, and expandability.

• Add a SATA/SAS HBA card (like the LSI 9211-8i flashed to IT mode) to support more than 6 drives cleanly.

• [EDIT:] Stick with the powerful stock HP 1125-watt power supply. Its 6-pin PCIe power cables can each deliver 12V x 18A = 216-watt of power, meaning, you can use 6-pin to 8-pin PCIe power adapter cables.

Kind Regards,

NonSequitur777

[mgbsher]

Thanks a lot for your helpful reply.

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@NonSequitur777 wrote:

1. Best for Expandability:

   Z840 is your top pick

---

I will follow your recommendations especially for the long run and go for the z840.

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@NonSequitur777 wrote:

• Add a SATA/SAS HBA card (like the LSI 9211-8i flashed to IT mode) to support more than 6 drives cleanly.

---

I will follow your recommendation here as well but there is something I want to clear it a little bit more.

Please, if I may ask, may you give more details about your suggestions mentioned here, as I did googled the suggestions you thankfully mentioned, and I found other members in other communities like reddit mentioned that they have some problems with some models, so please may you advise or recommend which specific model exactly to order from eBay for example, and which firmware version number I should keep an eye on it when buying, and if the item has an old firmware version, is it ok to buy it and update it in my own or it is a hard task and require a technician?

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@NonSequitur777 wrote:

• Install a modular ATX PSU if you plan to expand heavily -OEM PSUs may not have enough SATA power connectors. For that, you'll have to purchase a special power adapter cable to allow you to use an industry standard ATX power supply.

I will do follow your recommendation here as well.

Please, isn't the z840 has the 1125 power supply? I mean do I need to buy this extra Power Supply Unit? or I am mistaken in understanding your point?

Of course you are right regarding that I will need extra or more power for the SATA drives or if later on with more hard drives that could be added, so may I ask for which PSU one to order that do fit the HP z840 and have enough power for my scenario, so I do not order a wrong item.

I am really thankful and appreciated your fruitful help and glad that I've asked here and get a helpful replies from experienced and talented members like you.

Please, what are the recommended number of RAMs I should get for this machine, it has 16 slots, so shall I get 16 item with 16 GB for each or less or more? and is it a must to be ECC ones?

Thanks a lot for your valuable time helping me.

[NonSequitur777]

@mgbsher,

You're asking some excellent follow-up questions -happy to help clarify! I did edit the power supply question in my previous response. I was thinking to what some advanced users have created with custom wiring harnesses and dual-PSU setups (one for the motherboard/GPU, one just for the drives), but this is not practical for all intents and purposes.

 

So, about the ATX Power Supply for the Z840:

You are absolutely right to double-check this -and thank you for catching it!

The HP Z840 uses a proprietary power supply that is not directly compatible with standard ATX PSUs. Unlike the Z420/Z440/Z640, which have ATX power adapter cables available, the Z840’s PSU connects to a power distribution backplane, and no off-the-shelf ATX adapter cable currently exists for this system.

So here’s what I recommend:

• Stick with the stock 1125-watt HP power supply — it’s robust and powerful enough for most expansion scenarios.

• If you need more SATA power connectors, just use:

  • Molex-to-SATA adapters, or

  • SATA power splitters (e.g., 1 SATA to 2 or 4 SATA power branches)

• These are inexpensive and work well, especially if you balance the power load across multiple rails.

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Recommended SATA/SAS HBA Card (for 10+ drives):

If you're aiming to connect more than 6 SATA drives reliably, I suggest the following card:

LSI 9211-8i HBA, flashed to IT mode

• This card gives you 8 SATA ports (via 2 Mini-SAS to 4x SATA breakout cables)

• It’s highly compatible with Z840 and works well with TrueNAS, UnRAID, Proxmox, etc.

What to look for on eBay (if available):

• Model: LSI 9211-8i (or OEM versions like Dell H200, IBM M1015 — same chip)

• Flashed to IT mode (not IR mode — “IT” is for passthrough/raw disk access)

• Firmware version: Preferably P20.x (the latest is P20.00.07.00)

• If it comes with an older firmware, it’s okay -you can reportedly flash it yourself, perhaps @SDH or @DGroves can assist.

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PSU Capacity Question:

You're correct that the HP Z840 comes with a 1125-watt PSU, which is more than capable of handling:

• Dual Xeons

• A powerful GPU

• Multiple hard drives (even 10–12+)

• Each 6-pin PCIe power cable can deliver up to 216-watt (12V x 16A) of power, allowing the use of 6-pin to 8-pin PCIe power adapter cables

No need to replace it -just add SATA power splitters as needed.

---

RAM Recommendations:

• Z840 has 16 DIMM slots

• It supports up to 512 GB of ECC Registered DDR4 (RDIMM or LRDIMM)

• If you’re using both CPU sockets, install RAM evenly across both CPU channels

• For most home lab/virtualization use:

  • 128GB (8×16GB ECC RDIMM) is a solid sweet spot

  • You can start with 64GB (4×16GB ECC RDIMM) and expand later

• Yes, ECC RAM is required -it's a workstation/server board

• The HP Z840 Workstation can support a maximum of 1TB of RAM  8 x 128GB) with a single processor. The system has 16 DIMM slots, and each processor supports up to 4 channels of DDR4 memory. The maximum amount of RAM the HP Z840 Workstation can hold is 2TB (16 x 128GB) of Load Reduced server (LRDIMM) memory using two processors.

Kind Regards,

NonSequitur777

[DGroves]

the total drive count is misleading as it assumes that the 5.25 external bays and the 4 internal 3.5 hotswap bays are not using 2.5in SSD's if you go this route the z840 can hold quite a few more drives than the number s listed you will however need a pci-e SATA or SATA/SAS HBA card also the z840's unused pci-e slots can have  a SAS/SATA 2.5in drive on a card installed

by doing the above you can install 15 (or more) 2.5 in drives to the listed total for the z840

the same applies to the other models although the totals will be lower

https://global.icydock.com/product_74.html

https://www.networkhardwares.com/products/tougharmor-mb998sp-b-8x2-5-sata-7mm-drive-hot-swap-mobile-...

https://www.walmart.com/ip/Norco-B-Q2T5-5-25-to-Quad-2-5-Drive-Bay-Adapter-Bracket-also-can-fit-in-t...

16 port IT/Raid SAS/SATA pci-e card (can do sata or/and sas out of box at same time)

https://www.ebay.com/itm/286308649348

the z820/840 upgraded pwr 1250 watt supply can safely power these additional 2.5in drives not sure about the stock 850 watt unit to check simply add up each drives listed wattage and see if under the wattage for the power supplies rail that has the SATA/SAS power plugs

[mgbsher]

@NonSequitur777

@DGroves

I am really very much thankful for your replies.

You really opened my eyes on a whole new approach I never even think or knew about it at all.

I will study these solutions more because I am really newbie to this world.

I will go through these paths and feed you back.

Thanks a lot once again, and wish me luck.

[NonSequitur777]

@mgbsher,

You are quite welcome!

My incursion into HP's Zxxx Workstation real estate is relatively recent: see my HP Z440 Workstation and my current HP Z420 Workstation upgrade projects.  Others, like @DGroves and @SDH are the heavy weights in this area!

Kind Regards,

NonSequitur777

[mgbsher]

Bless you all.