Why B.U. are xeon series processors that cheap?

Question

Processors

I want to build my own server. And at first I immediately climbed to look for a powerful processor, and only then all the components for it.
And I noticed one feature.
Used Top-end Intel Xeon series processors are so cheap, but new processors are very expensive.
Let's say.
https://www.ebay.com/itm/QS-new-INTEL-XEON-E7-8880...
or here in Russia
https://www.avito.ru/moskva/tovary_dlya_kompyutera...
Goes beyond 10 cores, 20 then 4,000 per processor, and the INTEL XEON E7 line
. What is the catch of such cheapness?
The first thought was that these are hosting providers or data cents when updating processors, they simply sell costs.
Or because the generation of processors is outdated.
These are my guesses =)
But I wanted to know what the catch is to take such a used processor for such, as I think, little money?

Answer 1

1. avito - a position can be stolen, unnecessary, unprofitable, of little demand, defective = the price of a Boeing can be $1 at any other market ...
2. wear and tear - more or less large users have statistics of wear and tear of modern electronics (including lead-free solders, etc.)
3. Those same TDPs - one processor eating 10 or 30 W - it doesn't matter, a corridor in a data center with racks, each with 40 servers and each with 2-4-8 processors - this already completely different prices for power consumption, cooling and the cost of reserving capacities.

Answer 2

Xeon is a specialized server processor. It requires a server mother and server memory, it simply won't work on another one. It requires an appropriate PSU and cooling. It's stupid to run Windows on it - it requires server tasks :)
A BU server for a home for virtualization is quite a topic for an IT specialist;) If there is somewhere to put it, because it makes noise, an infection, stronger than usual ...

Answer 3

There is a whole market for these server processors to the average user. Desktop x79 and x99 motherboards are made that support all the necessary peripherals, they can work with both server and regular RAM. Xeon processors run on the same architecture as the Core series processors and do not require any additional solutions.
The advantage of these processors is multi-threading, cache size and multi-channel mode of operation with RAM, for the sake of this, the frequency of cores and buses for RAM is set, which can be critical for the average user, since in a number of his tasks it decides the performance per core, and not their number . The maximum frequency of e5 v4 series processors with RAM is 2400 MHz, v3 - 2133, and older processors do not support DDR4 at all. Also, the interface versions of these processors are no longer the most relevant, which may affect the speed of the peripherals.
As a result, when for servers they either develop their resource over time, or become irrelevant, they are sold at such a price as to compete with those user used processors with which they compete in performance. In overclocked condition! You also need to be able to overclock, you need to be able to cool it down, if the set power consumption level is exceeded, the computing power will be reset.
Further, the stepping of the processor affects the price. The first test samples of the processor, engineering versions, may be unstable in operation. Engineering and pre-release processors are sold cheaper than release ones. You can definitely find out the stepping only if you have it on hand, some sellers post a screenshot of CPU-Z.
It is more reliable to take such offers with Aliexpress, there are many years of stores of relevant products and user experience, some sellers say that they tested each sample for stability and promise a guarantee. There are also ready-made processor + board + RAM assemblies tested for stability.