Yes, your 32GiB card is an Ultra High Speed I [UHS-1], and it's actually hard to closely compare Class Speed [number in 'C'] and UHS Class [number in 'U'] because they have different testing standards. Class Speed states minimum write speed, but maximum write speed may be quite a lot higher and may vary considerably between card brands. Then again UHS-1 [only one class at the present] cards have speeds up to a maximum of 312 Megabytes per second, however i'm sure that can be a read speed [which is always faster than a card's write speed], so it's a little difficult to compare relative speeds of, say, SDHC Class 10 with SDHC/SDXC UHS-1. Probably we would mostly assume that the slowest UHS-1 is at least as fast as, and probably faster than the fastest SDHC Class 10. Not so, because UHS-1 cards may also indicate a Speed Class (number in a 'C') but i don't think that's mandatory the way it is with Standard and HC cards.... My Sandisk Ultra 64GiB UHS-1 has a Speed Class of 6. So, in theory, it's got a slower minimum write speed than my Class 10 16GiB card. Both Class 10 & UHS-1 are the only cards that can use a High Speed Bus Interface, while naturally only UHS-1 cards can use an Ultra High Speed Bus Interface. All cards are backwards compatible, but no current cards are forward compatible, i.e. Class 2, 4, and 6 cannot use either HS Bus or UHS-1 Bus Interfaces. Class 10 is therefore backwards compatible with Normal Bus Interface used by Class 2, 4 & 6. UHS-1 can use any of the 3 buses, but like Class 10, is naturally 'bottlenecked' by a slower bus. Afaik, Garmin devices [except maybe the very new ones] have Normal Bus Interface which slows the Class 10 & UHS-1 cards right down.

Confused? Welcome, it's a big club.

I prefer to get any info from the organisations responsible for the specific industry standards, in this case the SD Association, 'coz perhaps the so-called 'tech' sites actually may have a hidden agenda, but in this case i have to say that the site linked by mullerh gives exactly the same info as the official site albeit in a more conversational way. Here's the SD Association's page about Speed Classes:
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As to your 885 being slow to start and being a 'little' different, it's actually quite different to normal nuvis. Rather than the 'closed-shop' Garmin OS It has a Linux OS as you probably know. Although i've heard some mixed reports on the 805 series, i would like to get my hands on one. Hard to come by in this Country. But what i was referring to was the times to load the maps [when during boot-up, the screen displays 'Loading Maps' followed by the map info, just before the 'Warning' nag appears. It's easy to time that specific process for comparison.