You need to check the amount of available upper memory. Older system is more likely to have more free UMB room than newer one.

EMS requires a contiguous 64KB of UMB for its page frame which will be deducted from your available upper memory. Looks like your remaining upper memory is too low to hold all the TSRs. You may consider including the monochrome section (I=B000-B7FF) for 32KB more.

Additionally, do you use any PCI add-on cards with option ROMs? My personal experience was that the option ROM of PCI IDE/SATA cards (which enables booting) can take a good portion of upper memory (like 20KB or more) leaving less room for other TSRs. Onboard devices with option ROMs (such as controllers for additional IDE/SATA slots not provided by the chipset itself) also count. In that case, try disabling them from BIOS if not using them.

Modern video cards can additionally take up a varying amount of upper memory for its video BIOS functionalities. If you're not using other cards with option ROMs, chances are that the video card you're using took a bit more of UMB compared to your old system.

Should warn that if the system UMB space is too crowded to have a contiguous 64KB area, EMS will not work correctly (in JEMM386's case, you'll get a warning that it could not find a suitable page frame).

I also suggest you check out JEMM https://www.japheth.de/Jemm.html
I suppose it will be better suited to later chipsets (like P4).

CheckIt! has a nice memory browser. 😎 It not only shows the usage of conventional memory and the adapter segment, but also tells you what it's being used for.
Or alternatively, shows the first 84 bytes of an unknown segment.

LSS10999 wrote on 2022-05-17, 05:25:

You need to check the amount of available upper memory. Older system is more likely to have more free UMB room than newer one. […]
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You need to check the amount of available upper memory. Older system is more likely to have more free UMB room than newer one.

EMS requires a contiguous 64KB of UMB for its page frame which will be deducted from your available upper memory. Looks like your remaining upper memory is too low to hold all the TSRs. You may consider including the monochrome section (I=B000-B7FF) for 32KB more.

Additionally, do you use any PCI add-on cards with option ROMs? My personal experience was that the option ROM of PCI IDE/SATA cards (which enables booting) can take a good portion of upper memory (like 20KB or more) leaving less room for other TSRs. Onboard devices with option ROMs (such as controllers for additional IDE/SATA slots not provided by the chipset itself) also count. In that case, try disabling them from BIOS if not using them.

Modern video cards can additionally take up a varying amount of upper memory for its video BIOS functionalities. If you're not using other cards with option ROMs, chances are that the video card you're using took a bit more of UMB compared to your old system.

Should warn that if the system UMB space is too crowded to have a contiguous 64KB area, EMS will not work correctly (in JEMM386's case, you'll get a warning that it could not find a suitable page frame).

Other crap in the upper memory area to disable includes network/pxe boot and legacy USB keyboard/mouse support.

LSS10999 is right. It are the ROMS that are placed in the UMB space.
But also graphics card ROM sizes matter. Basically older graphics card have smaller ROMS that just occupy C000-C7FF. Newer cards take 64 kB and more.

One tip, for EMS & UMB, move the EMS page frame down to the top of the ROM, to avoid splitting the UMB into two spaces, that way you don't need tricky MEMMAKER zone selection for packing