Should I buy SFP+ or QSFP+ cards?

[inf3rno]

I already have two Mellanox ConnectX-3 SFP+ cards, they are working great and I am looking for a dual port SFP+ card to connect both of my computers to a third one. I noticed meanwhile, that there are QSFP+ cards with 40 Gbps and they are the same price or sometimes even cheaper than SFP+ cards. Is there a reason why they are so cheap even if they have 4x the bandwidth? I would move to QSFP+ if they really work without issues.

Another thing I ran into that there are "HP Mellanox" QSFP+ cards. Does this mean that Mellanox gives the controller chip and HP builds the card around it? If so, then does this matter e.g. will the transceiver, motherboard, etc. compatibility suffer or will it overheat just like many cards from HP? These cards appear to be significantly cheaper second hand than pure Mellanox cards...

 

[SamirD]

Not an expert in this by any means, but from what I've read, I would see if those 40Gb cards are infiniband or ethernet. Also, it seems the branded cards don't have the ability to upgrade to the Mellanox firmwares.

 

[inf3rno]

Not an expert in this by any means, but from what I've read, I would see if those 40Gb cards are infiniband or ethernet. Also, it seems the branded cards don't have the ability to upgrade to the Mellanox firmwares.

Some HP cards can be upgraded, for example HP MCX354A-QCBT can be upgraded to MCX354A-FCBT and the price is somewhat cheaper, so it would be great for what I need in my router. Though it would mean only 64 Gbps total because of the PCIE gen3 x8, but the connectx-4 with gen3 x16 is too expensive for me atm. and I want a compact router (mITX), so 2x8 is out of the question unless I do PCIE bifurcation for an extra $100 or more, which sounds weird in a $100-150 motherboard... The IB and ETH is a good point, for example Dell CX324A does 40 Gbps only on ETH, while most cards are IB, so that would be a bad choice. In my case what would make a real difference is being able to upgrade the Fujitsu A05954-2101 to a Mellanox firmware, because it is dirt cheap ($60 vs $105 for pulled cards), and I want to have connectx-3 with PCIE gen3 at least even for the single port cards. The connectx-2 cards are very cheap, but they support only PCIE gen2 and they are 10-15 years old while a connectx-3 cards support PCIE gen3 and are at most 10 years old... So if I go with these branded cards, then I can buy 2 single port and 1 dual port cards for 2x $60 + $100 = $220, while if I go with the Mellanox cards I can buy them for 2x $105 + $135 = $355, which is 60% more, which is huge if the branded cards can do the exact same thing. I would rather spend that extra $135 on a PCIE bifurcation riser or on the CPU.

 

[inf3rno]

I found a HP card seller in the EU and it is dirt cheap, around $30 compared to the alternatives here. I bought 2 and we'll see if they really arrive. I wonder why shipping is so expensive on ebay while free on ali...

 

[SamirD]

ali--fake illegals that violate IP rights by stealing designs so no real business cost to make them other than manufacturing. EU ones are probably real and pulls from a datacenter there.

 

[inf3rno]

ali--fake illegals that violate IP rights by stealing designs so no real business cost to make them other than manufacturing. EU ones are probably real and pulls from a datacenter there.

You might be right. I bought two MCX311A-XCAT from ali, and they look brand new. They work properly with Mellanox drivers, but now I don't know if they are real Mellanox products. And ofc. Chinese can easily add their own backdoors to them. Does not really matter though, I am about to replace them to QSFP+ cards.

 

[SamirD]

You might be right. I bought two MCX311A-XCAT from ali, and they look brand new. They work properly with Mellanox drivers, but now I don't know if they are real Mellanox products. And ofc. Chinese can easily add their own backdoors to them. Does not really matter though, I am about to replace them to QSFP+ cards.

Yep, this is exactly why any company that doesn't want fakes of their product flooding the market should stop manufacturing in china. I know the person in charge for the batteries on the iphone and the type of flat out illegal and violently unethical stuff that he's told me about manufacturing there has made sure I will never make any of my products there. You basically give up all your rights to everything including profit. F that and F those mothers...let them figure out how to be smart on their own...

Enjoy the upgrade!

 

[vxspiritxv]

Here's my post from awhile ago you should check out:
https://hardforum.com/threads/40-10gb-ethernet-under-500-noisy-but-fast-howto.1991874/

Just last week, I had a partial failure of the fan tray in my switch (4948e), decided to go quite instead of installing a 3064x that I have. Ended up getting Mikrotik 24 PoE + 4 sfp+. After searching a ton I found 40gig to 10gig adapters, kinda expensive, MAM1Q00A-QSA-SP. Arrives next week, so ill post an update if it doesn't work, otherwise assume it did. Anyways just putting this out there if for some reason need to run 10gig on 40gig card.

-edit-
Adapter just arrived, I can confirm it works. Used with a standard Finstar SR adapter (cisco & dell both rebrand Finstar).

Replaced my x520 with this, x520 had some random flapping.

Other end is a ESX/Windows dell server with Intel 82599EB (I believe that's an x520)