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Comment by willis936 | Hacker News Reader

From my experience any company that is developing interconnects either has the needed test equipment or uses a test house. It seems strange that access to test equipment should factor into an engineering decision.

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The test equipment is hundreds of thousands of dollars each and everything used for PCIe3 doesn't have the bandwidth to go to PCIe 4. The bigger companies have no problem scaling up but for smaller players it's a serious consideration. Even at satellite offices of larger companies, it can be difficult to get the capital outlay for your lab to buy something like a BERT. We're talking millions of dollars at scale. Fortunately, most of the equipment that works for PCIe4 will also work for PCIe5.

I worked in a test house for seven years. The last thing I did before I left is automate PAM4 25GBaud transmitter and receiver testing. I am intimately familiar with the costs. I am also familiar with how necessary it is for every player to have access to this equipment.

And so if there is a need to increase bandwidth there could be an engineering decision to either go with faster links or more links at the existing speed. Faster links has the extra cost of involving more expensive test equipment, more links does not. Strictly speaking perhaps engineering decisions should not consider cost and that's one for the bean counters, but I don't think that's the reality for smaller teams where those two worlds merge.

Engineering decisions absolutely include cost. It's part of the classic triangle: Cheap, Fast, Good; pick two (or one).

Yes but if cost is dictating the quality spec then you aren’t accomplishing anything of value.

You're right that a design, verification and test bench can easily rack-up several hundred thousand dollars worth of equipment.

But there are trade-offs that can lower the capital cost, like leasing the equipment, using a third party for aspects of the design/test, carefully evolving known good designs and simply budgeting a lot more for more PCB re-spins.

In the finally analysis those to want to make products in this domain aren't doing it on a shoestring budget, it's going to cost a lot no matter what.

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