(1) being the most performant, and (2) being the most recent build for running W98SE, and, accidentally, also XP x32 and W10 x64, fully supporting games using DX9.0c and EAX4.0, with exceptional framerates at FullHD on W98SE, very good framerates at FullHD on XP, and still acceptable framerates for FullHD on W10.
Sidenote: While (1) it is not the fastest build for XP, it is still in the upper 10%. A GTX 980 Ti (or same insane Titan) would be faster, but would grill my rig for sure, esp. the SB Audigy2 in the slot above the second GPU. There are of course faster builds with Intel CPUs - but those don't run W98SE ... 😉

Needs some minor INF-Modding for XP on the first build, so the GTX 970 is supported.
Needs some minor INF-modding and several hacks (now public domain) by rloew (RIP), to make the 7900 GTX run on on W98SE.
Needs some minor tricks on W98SE, so it does not see memory above 1GB, as otherwise it would crash.

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(1) My ultimate rig, running W98SE, XP and W10 (pics: On Retro Rig Photo thread).
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MoBo: ASRock 890FX Deluxe5
CPU: AMD FX-8350 (125W TDP, 4 GHz, 4 Modules/8 Cores)
Ram: 16GB (2 x 8GB Mushkin) (W98SE can see only 1GB of this by some black magic from MSFN)

GPU:
- Slot 1 (PCIe 2.0 8x): EVGA NVidia 7900 GTX PCIe 512MB
- Slot 2 (PCIe 2.0 8x): MANLI NVidia GTX 970 PCIe 4GB
Annotation: W98SE cannot see the GTX 970, while it is the main GPU for W10 and XP under normal circumstances.
I can configure the 7900 GTX to be used as the primary GPU on W10 and XP by installing the appropriate driver (309 Legacy for MS-W8.0), to compare games over different OS-Generations.

Sound: Soundblaster Audigy 2 PCI

Storage (W98SE cannot see port 1-4):
- Port 1: SuperTalent SSD 128GB SATA II (XP)
- Port 2: SanDisk SSD ExtremePro 480GB SATA III (W10)
- Port 3: LG BluRay SATA
- Port 4: <reserved for future use>
- Port 5: SuperTalent SSD 64 GB SATA II (W98SE) in IDE Mode
- Port 6: noname SATA DVD in ATAPI mode

LAN: TP-Link TG-3468 Gigabit PCIe

XP and W10 can also use and see USB3.0, W98SE cannot, of course.

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(2) My secondary build, with this being the most recent board (still in shops) running W98SE:
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MoBo: ASRock 970 Pro3 R2.0
CPU: AMD FX-4320 (95W TDP, 4 GHz, 2 Modules/4 Cores)
Ram: 16GB (4 x 4GB NoName DDR3 at stock settings) (W98SE can see only 1GB of this by some black magic from MSFN)

GPU: (PCIe 2.0 16x) EVGA NVidia 7900 GTX PCIe 512MB

Sound: Soundblaster Audigy 2 PCI

Storage (W98SE cannot see port 1-4):
- Port 1: SuperTalent SSD 128GB SATA II (XP)
- Port 2: Samsung SSD Pro 840 240GB SATA III (W10)
- Port 3: <reserved for future use>
- Port 4: <reserved for future use>
- Port 5: SuperTalent SSD 128 GB SATA II (W98SE) in IDE Mode
- Port 6: noname SATA DVD in ATAPI mode

LAN: TP-Link TG-3468 Gigabit PCIe

XP and W10 can also use and see USB3.0, W98SE cannot, of course.